|
Eddie Walsh
|
|
|
Group: Forum Members
Posts: 52,
Visits: 294
|
+x+x+x+x+x+x+xWhen you rub or break by hand a powder pound CSM, then usually you will get a white powder falling off as you rub or break it. Vacuum bagging is generally not necessary. For example, the putty if correctly applied, will fill the sharp corners and recesseses - thus no voids. The laying up of the cloth is then much easier and just requires good quality laminating by hand to achieve a void free finish. So there is little to gain from vacuum bagging that hasn't already been achieved through proper and good quality laminating. In theory it may well help for very high temperature applications but this is rare and i have not heard of anyone vacuum bagging the moulds even in this situation. I would expand on what Warren said - The important part is getting the gel coat into all the corners and crevices. As this is like a very thick paint when warm, you can't vacuum bag it as it will simply squish all over the place!. You then add the paste whilst the gel coat is still tacky (but firm enough that pushing on the paste doesn't disturb it- correct me if I am wrong Warren or Paul, but I use the fingerprint test, if my finger leaves a print but the gel doesn't come off on my finger it is ready for the next stage) and then add the fibreglass over the whole lot. For smallish parts I use an old domestic oven bought from eBay. There are plenty on there, here is an example. Simply drill a hole through the side for the vacuum tube :-) https://www.ebay.co.uk/itm/neff-Electric-oven-You-Arrange-Courier-Or-Collect/323346305953?hash=item4b48f113a1%3Ag%3AKUAAAOSwpz5bR6-N&_sacat=0&_nkw=domestic+oven+electric&_from=R40&LH_ItemCondition=4&rt=nc&_trksid=m570.l1313 Hi Steve, Don't get me wrong, but I know the basics as I have been doing Fiberglas for over 30 years, so I have lots of Moulds and am forever repairing then, mainly because they were not made well to start with, none have been Vacuum Bagged, so now I want to start learning the correct way and Materials to do CF, so want to start with Hand Layup and Air dry, and if I get on with then I will buy a large oven to accommodate large panels such as Bonnets, doors, Undertrays, the Ferrari Undertrays are very large approx 6ft X 4.5 ft, so I do not want to run before I can walk, Like I said to Warren the Mould is the most important tool as it is going to be used lots of times, and especially if you have a perfect item to Mould the last thing you want to be doing is repairs to a new Mould, so when I found this Forum I was hoping for some great advice, but when someone says no need to VB your Mould I find it very hard to believe that that is best practice, so anyway I will persevere and try VBing my Moulds, so thanks for all you advice and help, I will let you know how I get on, Regards DM I don't get you wrong :-) This is a great place to throw around ideas. Once the gel coat has cured sufficiently so that you can add the paste, no amount of vacuum bagging will improve matters. However, there is no harm in vacuum bagging the fibreglass but you are wasting a lot of time and materials for no advantage, IMO. The guys stating there is no need to vacuum the mould work at EC so they do know what they are talking about. Matt is the guy in the videos :-) I made my own large oven (6' x 6' x 3') to accommodate my flip front. Easy to make and it is powered by 150w light bulbs :-) These are spread around the perimeter helping to even out the temp (this is also a large fan).  Hi Steve, I am now convinced that I cannot VB my Mould so again Thanks for your help and advice an old dog like me has to be convinced ???,your oven sounds good what is it made of and how do you control the temperature, I have seen on some of the Video's where the temp has to be increased every Hour up to a max ??, other good news my spare Airbox has arrived this morning so I will have to start buying my materials soon from EC and get started,so again Thanks for all your help and Patience, Regards DM No problem :-) My oven is as simple as I could make it, mostly made from stuff lying around. The frame is 2 x 2 infilled with 2" insulation board. Internally it is lined (walls, ceiling and floor) with ply and heat reflective foil and clad outside with ply. Heating is provided by 150w bulbs. However, in order to have control of both temp ramp and final temp, I wired them there are 4 circuits, each controlled by a light switch. An additional circuit is controlled by an adjustable thermostat so I am able to set the required max temp. So far it has worked pretty well, as long as I am not in a hurry as to get to 120deg C takes around an hour or so :-) I have a fan so the air get circulated and 8 thermometers scattered around the oven so I can monitor that the oven is heating up evenly. I plan to add additional circuits in order to speed up the heating process. At the moment it maxes out around 130 deg C, which is high enough for my purposes. I used the glass out of an old microwave as a window so I could check on progress without having to open the door.   .  Hi Steve, your oven sounds great, and as you sayif it does the job then what more do you want, I might have a go if I get on with the CF, so again Thanks, Regards DM Hi Matt, Can you do me a list of what I will need to make the Mould and Air Box in carbon fibre,also the Vacuum Bagging materials, Thanks, Regards DM
|
|
|
|
|
Eddie Walsh
|
|
|
Group: Forum Members
Posts: 52,
Visits: 294
|
+x+x+x+x+x+xWhen you rub or break by hand a powder pound CSM, then usually you will get a white powder falling off as you rub or break it. Vacuum bagging is generally not necessary. For example, the putty if correctly applied, will fill the sharp corners and recesseses - thus no voids. The laying up of the cloth is then much easier and just requires good quality laminating by hand to achieve a void free finish. So there is little to gain from vacuum bagging that hasn't already been achieved through proper and good quality laminating. In theory it may well help for very high temperature applications but this is rare and i have not heard of anyone vacuum bagging the moulds even in this situation. I would expand on what Warren said - The important part is getting the gel coat into all the corners and crevices. As this is like a very thick paint when warm, you can't vacuum bag it as it will simply squish all over the place!. You then add the paste whilst the gel coat is still tacky (but firm enough that pushing on the paste doesn't disturb it- correct me if I am wrong Warren or Paul, but I use the fingerprint test, if my finger leaves a print but the gel doesn't come off on my finger it is ready for the next stage) and then add the fibreglass over the whole lot. For smallish parts I use an old domestic oven bought from eBay. There are plenty on there, here is an example. Simply drill a hole through the side for the vacuum tube :-) https://www.ebay.co.uk/itm/neff-Electric-oven-You-Arrange-Courier-Or-Collect/323346305953?hash=item4b48f113a1%3Ag%3AKUAAAOSwpz5bR6-N&_sacat=0&_nkw=domestic+oven+electric&_from=R40&LH_ItemCondition=4&rt=nc&_trksid=m570.l1313 Hi Steve, Don't get me wrong, but I know the basics as I have been doing Fiberglas for over 30 years, so I have lots of Moulds and am forever repairing then, mainly because they were not made well to start with, none have been Vacuum Bagged, so now I want to start learning the correct way and Materials to do CF, so want to start with Hand Layup and Air dry, and if I get on with then I will buy a large oven to accommodate large panels such as Bonnets, doors, Undertrays, the Ferrari Undertrays are very large approx 6ft X 4.5 ft, so I do not want to run before I can walk, Like I said to Warren the Mould is the most important tool as it is going to be used lots of times, and especially if you have a perfect item to Mould the last thing you want to be doing is repairs to a new Mould, so when I found this Forum I was hoping for some great advice, but when someone says no need to VB your Mould I find it very hard to believe that that is best practice, so anyway I will persevere and try VBing my Moulds, so thanks for all you advice and help, I will let you know how I get on, Regards DM I don't get you wrong :-) This is a great place to throw around ideas. Once the gel coat has cured sufficiently so that you can add the paste, no amount of vacuum bagging will improve matters. However, there is no harm in vacuum bagging the fibreglass but you are wasting a lot of time and materials for no advantage, IMO. The guys stating there is no need to vacuum the mould work at EC so they do know what they are talking about. Matt is the guy in the videos :-) I made my own large oven (6' x 6' x 3') to accommodate my flip front. Easy to make and it is powered by 150w light bulbs :-) These are spread around the perimeter helping to even out the temp (this is also a large fan). Hi Steve, I am now convinced that I cannot VB my Mould so again Thanks for your help and advice an old dog like me has to be convinced ???,your oven sounds good what is it made of and how do you control the temperature, I have seen on some of the Video's where the temp has to be increased every Hour up to a max ??, other good news my spare Airbox has arrived this morning so I will have to start buying my materials soon from EC and get started,so again Thanks for all your help and Patience, Regards DM No problem :-) My oven is as simple as I could make it, mostly made from stuff lying around. The frame is 2 x 2 infilled with 2" insulation board. Internally it is lined (walls, ceiling and floor) with ply and heat reflective foil and clad outside with ply. Heating is provided by 150w bulbs. However, in order to have control of both temp ramp and final temp, I wired them there are 4 circuits, each controlled by a light switch. An additional circuit is controlled by an adjustable thermostat so I am able to set the required max temp. So far it has worked pretty well, as long as I am not in a hurry as to get to 120deg C takes around an hour or so :-) I have a fan so the air get circulated and 8 thermometers scattered around the oven so I can monitor that the oven is heating up evenly. I plan to add additional circuits in order to speed up the heating process. At the moment it maxes out around 130 deg C, which is high enough for my purposes. I used the glass out of an old microwave as a window so I could check on progress without having to open the door. . Hi Steve, your oven sounds great, and as you sayif it does the job then what more do you want, I might have a go if I get on with the CF, so again Thanks, Regards DM
|
|
|
|
|
Steve Broad
|
|
|
Group: Forum Members
Posts: 408,
Visits: 4.1K
|
+x+x+x+x+xWhen you rub or break by hand a powder pound CSM, then usually you will get a white powder falling off as you rub or break it. Vacuum bagging is generally not necessary. For example, the putty if correctly applied, will fill the sharp corners and recesseses - thus no voids. The laying up of the cloth is then much easier and just requires good quality laminating by hand to achieve a void free finish. So there is little to gain from vacuum bagging that hasn't already been achieved through proper and good quality laminating. In theory it may well help for very high temperature applications but this is rare and i have not heard of anyone vacuum bagging the moulds even in this situation. I would expand on what Warren said - The important part is getting the gel coat into all the corners and crevices. As this is like a very thick paint when warm, you can't vacuum bag it as it will simply squish all over the place!. You then add the paste whilst the gel coat is still tacky (but firm enough that pushing on the paste doesn't disturb it- correct me if I am wrong Warren or Paul, but I use the fingerprint test, if my finger leaves a print but the gel doesn't come off on my finger it is ready for the next stage) and then add the fibreglass over the whole lot. For smallish parts I use an old domestic oven bought from eBay. There are plenty on there, here is an example. Simply drill a hole through the side for the vacuum tube :-) https://www.ebay.co.uk/itm/neff-Electric-oven-You-Arrange-Courier-Or-Collect/323346305953?hash=item4b48f113a1%3Ag%3AKUAAAOSwpz5bR6-N&_sacat=0&_nkw=domestic+oven+electric&_from=R40&LH_ItemCondition=4&rt=nc&_trksid=m570.l1313 Hi Steve, Don't get me wrong, but I know the basics as I have been doing Fiberglas for over 30 years, so I have lots of Moulds and am forever repairing then, mainly because they were not made well to start with, none have been Vacuum Bagged, so now I want to start learning the correct way and Materials to do CF, so want to start with Hand Layup and Air dry, and if I get on with then I will buy a large oven to accommodate large panels such as Bonnets, doors, Undertrays, the Ferrari Undertrays are very large approx 6ft X 4.5 ft, so I do not want to run before I can walk, Like I said to Warren the Mould is the most important tool as it is going to be used lots of times, and especially if you have a perfect item to Mould the last thing you want to be doing is repairs to a new Mould, so when I found this Forum I was hoping for some great advice, but when someone says no need to VB your Mould I find it very hard to believe that that is best practice, so anyway I will persevere and try VBing my Moulds, so thanks for all you advice and help, I will let you know how I get on, Regards DM I don't get you wrong :-) This is a great place to throw around ideas. Once the gel coat has cured sufficiently so that you can add the paste, no amount of vacuum bagging will improve matters. However, there is no harm in vacuum bagging the fibreglass but you are wasting a lot of time and materials for no advantage, IMO. The guys stating there is no need to vacuum the mould work at EC so they do know what they are talking about. Matt is the guy in the videos :-) I made my own large oven (6' x 6' x 3') to accommodate my flip front. Easy to make and it is powered by 150w light bulbs :-) These are spread around the perimeter helping to even out the temp (this is also a large fan). Hi Steve, I am now convinced that I cannot VB my Mould so again Thanks for your help and advice an old dog like me has to be convinced ???,your oven sounds good what is it made of and how do you control the temperature, I have seen on some of the Video's where the temp has to be increased every Hour up to a max ??, other good news my spare Airbox has arrived this morning so I will have to start buying my materials soon from EC and get started,so again Thanks for all your help and Patience, Regards DM No problem :-) My oven is as simple as I could make it, mostly made from stuff lying around. The frame is 2 x 2 infilled with 2" insulation board. Internally it is lined (walls, ceiling and floor) with ply and heat reflective foil and clad outside with ply. Heating is provided by 150w bulbs. However, in order to have control of both temp ramp and final temp, I wired them there are 4 circuits, each controlled by a light switch. An additional circuit is controlled by an adjustable thermostat so I am able to set the required max temp. So far it has worked pretty well, as long as I am not in a hurry as to get to 120deg C takes around an hour or so :-) I have a fan so the air get circulated and 8 thermometers scattered around the oven so I can monitor that the oven is heating up evenly. I plan to add additional circuits in order to speed up the heating process. At the moment it maxes out around 130 deg C, which is high enough for my purposes. I used the glass out of an old microwave as a window so I could check on progress without having to open the door. .
|
|
|
|
|
Eddie Walsh
|
|
|
Group: Forum Members
Posts: 52,
Visits: 294
|
+x+x+x+xWhen you rub or break by hand a powder pound CSM, then usually you will get a white powder falling off as you rub or break it. Vacuum bagging is generally not necessary. For example, the putty if correctly applied, will fill the sharp corners and recesseses - thus no voids. The laying up of the cloth is then much easier and just requires good quality laminating by hand to achieve a void free finish. So there is little to gain from vacuum bagging that hasn't already been achieved through proper and good quality laminating. In theory it may well help for very high temperature applications but this is rare and i have not heard of anyone vacuum bagging the moulds even in this situation. I would expand on what Warren said - The important part is getting the gel coat into all the corners and crevices. As this is like a very thick paint when warm, you can't vacuum bag it as it will simply squish all over the place!. You then add the paste whilst the gel coat is still tacky (but firm enough that pushing on the paste doesn't disturb it- correct me if I am wrong Warren or Paul, but I use the fingerprint test, if my finger leaves a print but the gel doesn't come off on my finger it is ready for the next stage) and then add the fibreglass over the whole lot. For smallish parts I use an old domestic oven bought from eBay. There are plenty on there, here is an example. Simply drill a hole through the side for the vacuum tube :-) https://www.ebay.co.uk/itm/neff-Electric-oven-You-Arrange-Courier-Or-Collect/323346305953?hash=item4b48f113a1%3Ag%3AKUAAAOSwpz5bR6-N&_sacat=0&_nkw=domestic+oven+electric&_from=R40&LH_ItemCondition=4&rt=nc&_trksid=m570.l1313 Hi Steve, Don't get me wrong, but I know the basics as I have been doing Fiberglas for over 30 years, so I have lots of Moulds and am forever repairing then, mainly because they were not made well to start with, none have been Vacuum Bagged, so now I want to start learning the correct way and Materials to do CF, so want to start with Hand Layup and Air dry, and if I get on with then I will buy a large oven to accommodate large panels such as Bonnets, doors, Undertrays, the Ferrari Undertrays are very large approx 6ft X 4.5 ft, so I do not want to run before I can walk, Like I said to Warren the Mould is the most important tool as it is going to be used lots of times, and especially if you have a perfect item to Mould the last thing you want to be doing is repairs to a new Mould, so when I found this Forum I was hoping for some great advice, but when someone says no need to VB your Mould I find it very hard to believe that that is best practice, so anyway I will persevere and try VBing my Moulds, so thanks for all you advice and help, I will let you know how I get on, Regards DM I don't get you wrong :-) This is a great place to throw around ideas. Once the gel coat has cured sufficiently so that you can add the paste, no amount of vacuum bagging will improve matters. However, there is no harm in vacuum bagging the fibreglass but you are wasting a lot of time and materials for no advantage, IMO. The guys stating there is no need to vacuum the mould work at EC so they do know what they are talking about. Matt is the guy in the videos :-) I made my own large oven (6' x 6' x 3') to accommodate my flip front. Easy to make and it is powered by 150w light bulbs :-) These are spread around the perimeter helping to even out the temp (this is also a large fan). Hi Steve, I am now convinced that I cannot VB my Mould so again Thanks for your help and advice an old dog like me has to be convinced ???,your oven sounds good what is it made of and how do you control the temperature, I have seen on some of the Video's where the temp has to be increased every Hour up to a max ??, other good news my spare Airbox has arrived this morning so I will have to start buying my materials soon from EC and get started,so again Thanks for all your help and Patience, Regards DM
|
|
|
|
|
Eddie Walsh
|
|
|
Group: Forum Members
Posts: 52,
Visits: 294
|
+xHi Dinoman, To make sure everything all stays positive I think it's clear you've got a procedure in your mind that you want to follow and that's totally fine. In composites, I think we've all learned that there's usually several ways to achieve just about any task and each of us can only say what works for us. From an Easy Composites perspective we tend to take things a little further and experiment with lots of different techniques so that we can provide added value to our customers (i.e. saving them from false starts) because we're less constrained in terms of resources, materials and expertise. We did do quite a bit of research (I'm talking hundreds of test panels) of vacuum bagging moulds for high temperature use and it didn't provide the benefits we were looking for (vacuum bagging doesn't eliminate the potential for air pockets between gel and reinforcement). Resin infusion - on the other hand - is a different story and resin infusing a mould does make a lot of sense and works well, however it's often impractical to do because you really need to be working on a solid pattern (either a splash part or tooling board) rather than an original with temporary barriers, etc. I hope you the input from ourselves and other members useful, I'll be be interested to hear how you get on and of course be ready to learn something from your results. All the best, Matt Hi Matt, as you can see I am coming round to your way and everyone else's after Hanaldo pointed out the flaws in my thinking, so again Thanks for all your patience and a great Forum, Regards DM
|
|
|
|
|
Eddie Walsh
|
|
|
Group: Forum Members
Posts: 52,
Visits: 294
|
+xYou are over thinking this. You do not need vacuum for making your mould, vacuum is only going to cause you trouble. If you had a solid pattern then I'd say go for it (albeit still totally unnecessary), but you don't. You will be using temporary flanges, which will not be able to handle the vacuum. If you use fluted signboard, this will crush under vacuum. If you use solid polypropylene sheet or even metal flanges - they are still temporary and will be distorted and pulled away from the position you want them in. In all scenarios, you have a piece that isn't suited for vacuum at all. It is perfectly possible to make a mould like this without vacuum without any voids what-so-ever. Use the right processes and materials, dont try to shoehorn in a process that doesn't suit what you are working with. Hi Hanaldo, now that is a very good reason not to VB my mould ??, I had not thought the Vacuum would exert and twisting or bending force on my flanges and as you say I would be VB when everything is still uncured so really flexible and easily moved out of position and possibly ruined, so again Thanks you have saved me a lot of heartache and time and materials, Regards DM
|
|
|
|
|
Matt (Staff)
|
|
|
Group: Forum Members
Posts: 680,
Visits: 1.9K
|
Hi Dinoman,
To make sure everything all stays positive I think it's clear you've got a procedure in your mind that you want to follow and that's totally fine. In composites, I think we've all learned that there's usually several ways to achieve just about any task and each of us can only say what works for us.
From an Easy Composites perspective we tend to take things a little further and experiment with lots of different techniques so that we can provide added value to our customers (i.e. saving them from false starts) because we're less constrained in terms of resources, materials and expertise. We did do quite a bit of research (I'm talking hundreds of test panels) of vacuum bagging moulds for high temperature use and it didn't provide the benefits we were looking for (vacuum bagging doesn't eliminate the potential for air pockets between gel and reinforcement). Resin infusion - on the other hand - is a different story and resin infusing a mould does make a lot of sense and works well, however it's often impractical to do because you really need to be working on a solid pattern (either a splash part or tooling board) rather than an original with temporary barriers, etc.
I hope you the input from ourselves and other members useful, I'll be be interested to hear how you get on and of course be ready to learn something from your results.
All the best, Matt
Matt Statham
Easy Composites / Carbon Mods - Technical Sales
|
|
|
|
|
Hanaldo
|
|
|
Group: Forum Members
Posts: 2.5K,
Visits: 28K
|
You are over thinking this. You do not need vacuum for making your mould, vacuum is only going to cause you trouble. If you had a solid pattern then I'd say go for it (albeit still totally unnecessary), but you don't. You will be using temporary flanges, which will not be able to handle the vacuum. If you use fluted signboard, this will crush under vacuum. If you use solid polypropylene sheet or even metal flanges - they are still temporary and will be distorted and pulled away from the position you want them in.
In all scenarios, you have a piece that isn't suited for vacuum at all. It is perfectly possible to make a mould like this without vacuum without any voids what-so-ever. Use the right processes and materials, dont try to shoehorn in a process that doesn't suit what you are working with.
|
|
|
|
|
Eddie Walsh
|
|
|
Group: Forum Members
Posts: 52,
Visits: 294
|
+x+x+x+xWhen you rub or break by hand a powder pound CSM, then usually you will get a white powder falling off as you rub or break it. Vacuum bagging is generally not necessary. For example, the putty if correctly applied, will fill the sharp corners and recesseses - thus no voids. The laying up of the cloth is then much easier and just requires good quality laminating by hand to achieve a void free finish. So there is little to gain from vacuum bagging that hasn't already been achieved through proper and good quality laminating. In theory it may well help for very high temperature applications but this is rare and i have not heard of anyone vacuum bagging the moulds even in this situation. I would expand on what Warren said - The important part is getting the gel coat into all the corners and crevices. As this is like a very thick paint when warm, you can't vacuum bag it as it will simply squish all over the place!. You then add the paste whilst the gel coat is still tacky (but firm enough that pushing on the paste doesn't disturb it- correct me if I am wrong Warren or Paul, but I use the fingerprint test, if my finger leaves a print but the gel doesn't come off on my finger it is ready for the next stage) and then add the fibreglass over the whole lot. For smallish parts I use an old domestic oven bought from eBay. There are plenty on there, here is an example. Simply drill a hole through the side for the vacuum tube :-) https://www.ebay.co.uk/itm/neff-Electric-oven-You-Arrange-Courier-Or-Collect/323346305953?hash=item4b48f113a1%3Ag%3AKUAAAOSwpz5bR6-N&_sacat=0&_nkw=domestic+oven+electric&_from=R40&LH_ItemCondition=4&rt=nc&_trksid=m570.l1313 Hi Steve, Don't get me wrong, but I know the basics as I have been doing Fiberglas for over 30 years, so I have lots of Moulds and am forever repairing then, mainly because they were not made well to start with, none have been Vacuum Bagged, so now I want to start learning the correct way and Materials to do CF, so want to start with Hand Layup and Air dry, and if I get on with then I will buy a large oven to accommodate large panels such as Bonnets, doors, Undertrays, the Ferrari Undertrays are very large approx 6ft X 4.5 ft, so I do not want to run before I can walk, Like I said to Warren the Mould is the most important tool as it is going to be used lots of times, and especially if you have a perfect item to Mould the last thing you want to be doing is repairs to a new Mould, so when I found this Forum I was hoping for some great advice, but when someone says no need to VB your Mould I find it very hard to believe that that is best practice, so anyway I will persevere and try VBing my Moulds, so thanks for all you advice and help, I will let you know how I get on, Regards DM I don't get you wrong :-) This is a great place to throw around ideas. Once the gel coat has cured sufficiently so that you can add the paste, no amount of vacuum bagging will improve matters. However, there is no harm in vacuum bagging the fibreglass but you are wasting a lot of time and materials for no advantage, IMO. The guys stating there is no need to vacuum the mould work at EC so they do know what they are talking about. Matt is the guy in the videos :-) I made my own large oven (6' x 6' x 3') to accommodate my flip front. Easy to make and it is powered by 150w light bulbs :-) These are spread around the perimeter helping to even out the temp (this is also a large fan). Hi Steve, thanks again, but as I have learned over the years it is never the fault of the gel coat it is always what is on top of it, the gel is just like paint so never a problem it is only when air is trapped between the Gel and Mat that the problems arise as the resin and mat cures there is a localised hot spot where the air is trapped so crinkles up your gel coat,and as far as I can see one sure way to try and avoid this is to VB, now maybe I am thinking all my problems will be solved if I VB everything and if I am proved wrong then I will be the first one to apologise to Matt and Warren, so again Thanks, Regards DM
|
|
|
|
|
Steve Broad
|
|
|
Group: Forum Members
Posts: 408,
Visits: 4.1K
|
+x+x+xWhen you rub or break by hand a powder pound CSM, then usually you will get a white powder falling off as you rub or break it. Vacuum bagging is generally not necessary. For example, the putty if correctly applied, will fill the sharp corners and recesseses - thus no voids. The laying up of the cloth is then much easier and just requires good quality laminating by hand to achieve a void free finish. So there is little to gain from vacuum bagging that hasn't already been achieved through proper and good quality laminating. In theory it may well help for very high temperature applications but this is rare and i have not heard of anyone vacuum bagging the moulds even in this situation. I would expand on what Warren said - The important part is getting the gel coat into all the corners and crevices. As this is like a very thick paint when warm, you can't vacuum bag it as it will simply squish all over the place!. You then add the paste whilst the gel coat is still tacky (but firm enough that pushing on the paste doesn't disturb it- correct me if I am wrong Warren or Paul, but I use the fingerprint test, if my finger leaves a print but the gel doesn't come off on my finger it is ready for the next stage) and then add the fibreglass over the whole lot. For smallish parts I use an old domestic oven bought from eBay. There are plenty on there, here is an example. Simply drill a hole through the side for the vacuum tube :-) https://www.ebay.co.uk/itm/neff-Electric-oven-You-Arrange-Courier-Or-Collect/323346305953?hash=item4b48f113a1%3Ag%3AKUAAAOSwpz5bR6-N&_sacat=0&_nkw=domestic+oven+electric&_from=R40&LH_ItemCondition=4&rt=nc&_trksid=m570.l1313 Hi Steve, Don't get me wrong, but I know the basics as I have been doing Fiberglas for over 30 years, so I have lots of Moulds and am forever repairing then, mainly because they were not made well to start with, none have been Vacuum Bagged, so now I want to start learning the correct way and Materials to do CF, so want to start with Hand Layup and Air dry, and if I get on with then I will buy a large oven to accommodate large panels such as Bonnets, doors, Undertrays, the Ferrari Undertrays are very large approx 6ft X 4.5 ft, so I do not want to run before I can walk, Like I said to Warren the Mould is the most important tool as it is going to be used lots of times, and especially if you have a perfect item to Mould the last thing you want to be doing is repairs to a new Mould, so when I found this Forum I was hoping for some great advice, but when someone says no need to VB your Mould I find it very hard to believe that that is best practice, so anyway I will persevere and try VBing my Moulds, so thanks for all you advice and help, I will let you know how I get on, Regards DM I don't get you wrong :-) This is a great place to throw around ideas. Once the gel coat has cured sufficiently so that you can add the paste, no amount of vacuum bagging will improve matters. However, there is no harm in vacuum bagging the fibreglass but you are wasting a lot of time and materials for no advantage, IMO. The guys stating there is no need to vacuum the mould work at EC so they do know what they are talking about. Matt is the guy in the videos :-) I made my own large oven (6' x 6' x 3') to accommodate my flip front. Easy to make and it is powered by 150w light bulbs :-) These are spread around the perimeter helping to even out the temp (this is also a large fan).
|
|
|
|