|
TURK
|
|
|
Group: Forum Members
Posts: 101,
Visits: 662
|
Hanaldo (12/11/2015)
Why are you not filling the low spots with body filler? Hi Hanaldo, Good question, normally that would be the way to go ........ but at the stage where I'm currently at ( 20 odd coats of pattern-coat primer ) I can't ....... or rather I'm afraid to 'undo' all the work I've already done. If I were hand laying or bagging carbon fibre I think it wouldn't matter, but I'm using my plugs as 'tooling plugs' for vacuum forming. As that process involves subjecting the plugs to high heat, the build-up of pattern-coat primer acts as a shell if you like, as pattern-coat primer has aluminium in it. If I go and fill the low spots with body filler now, I'll only create weak spots in that heat resistant 'shell'. I've had issues in the past with thin layers of polyester filler cracking due to heat, so I really don't want to risk it at this stage, so I'm having to use the pattern-coat primer as a filler as it were. As the OP was commenting on the pattern-coat primer as a product, I thought I had to pitch-in with my findings ........ that is to say, it doesn't actually do what it pertains on the Data Sheet ! It's seen as a very high viscosity primer almost like syrup, so a couple of coats of pattern-coat primer and you're done. I can assure that is not the case ......... it may become thicker in the last two minutes of it's pot life, but the initial mixture is more like regular emulsion paint. I had to build up my plugs by 2mm as they have to fit inside a bracket, so with the Data Sheet I concluded that 2 coats of 1mm each would be enough ........ it's taken 20 coats to get to that stage ! Don't get me wrong, I'm not complaining about the actual product as it's doing what I want it to. But the Data Sheet information is very misleading 
Next time I'll be looking for a different product, something much thicker but also very durable as I have to able to vacuum form many many parts from it. |
|
|
|
|
Hanaldo
|
|
|
Group: Forum Members
Posts: 2.5K,
Visits: 28K
|
Why are you not filling the low spots with body filler?
|
|
|
|
|
TURK
|
|
|
Group: Forum Members
Posts: 101,
Visits: 662
|
That's very interesting what you're saying Ian Mantula, and the rest of the members all basically saying the same thing. I was quite surprised myself when I began applying the Pattern-Coat Coat Primer ....... still am ........ as I'm now on my 20th coat ! I have to admit that I should really have built my MDF plug a little closer to the dimensions I required, by adding a little polyester body filler. But as I went by the products data sheet, which indicated that it brushed on at 1mm to 1.5mm thickness ....... not likely ! It took me by surprise as it's more like regular paint ! Here's where I am at the moment with my project > http://www.vwt4forum.co.uk/showthread.php?t=249064&page=150I still think it's great stuff, but an awful lot of work to get right >>  I'm not using my plugs for fibreglassing but for vacuum forming, one thing I can say is, the finish I currently have is solid, almost like slate !  |
|
|
|
|
TCS
|
|
|
Group: Forum Members
Posts: 13,
Visits: 52
|
Has anyone had any experience using Durabuild? Wondered what peoples experiences were vs using Pattern Coat Primer. Always used Durabuild myself but have a tin of PC primer sat there waiting for my usual Durabuild to run out. We've also used Llewellyn Rylands pattern primer which I actually prefer to Durabuild. We apply all systems by spray to reduce sanding operations
|
|
|
|
|
Hanaldo
|
|
|
Group: Forum Members
Posts: 2.5K,
Visits: 28K
|
Yeh it's a pity that Duratec products are so hard to get hold of. I've actually lost my supplier here too, they no longer sell it, so I'm on the search for an alternative. Have found a high build PU that may be similar, so will see how it goes.
|
|
|
|
|
MarkMK
|
|
|
Group: Forum Members
Posts: 338,
Visits: 2K
|
No, I haven't, 'though considering getting one at the moment to try some clear-coating. I'd have like to have tried the Duratec Sunshield I've seen you mention a few times, but struggling to find it here in the UK
It sounds like this type of gun might work well for applying the in-mould coating on some of the smaller moulds as well, so I might try on those
Cheers
|
|
|
|
|
Hanaldo
|
|
|
Group: Forum Members
Posts: 2.5K,
Visits: 28K
|
Have you tried spraying the coatings through a regular HVLP gun? I have sprayed tooling gelcoat with a 2.5mm tip on a HVLP gun and that worked very well, so I would think that these coatings would work too. Easier than the G100 for smaller parts.
|
|
|
|
|
MarkMK
|
|
|
Group: Forum Members
Posts: 338,
Visits: 2K
|
Bit of a thread revival, but recently picked up a FN4 nozzle for the G100 cup gun and it's much easier to control the spraying with this smaller diameter one. Easier to mist on and avoid the primer/gloss coat running and a more even finish too. Made flatting back more straightforward, so highly recommended over the FN6 nozzle for this application, at least
|
|
|
|
|
MarkMK
|
|
|
Group: Forum Members
Posts: 338,
Visits: 2K
|
If it's of any comfort Ian, I don't think I've yet managed to create a pattern that has a completeley uniform finish to it. Even parts where I'd applied a separate coat of pure gloss have sections where I've gone through to the primer underneath. Not an issue usually as you can polish the resultant mould up to a uniform finish. Have to be wary of bare sections of filler, mind, as these can end up stuck to your mould surface. I have, however, gotten away with gloss directly over bare areas of flatted filler. Probably best to keep the primer flatting to a minimum, to avoid total breakthrough and save the hard work for the final gloss coat, whilst accepting that you might get some patches of primer showing through the polished-up pattern.
|
|
|
|
|
Ian Mantula
|
|
|
Group: Forum Members
Posts: 24,
Visits: 668
|
Thanks for all of the feedback. It's nice to know that it's not just me! I'm getting better at this now, but I guess there is a lot to learn and practice is the only way to improve.
|
|
|
|