precaution when trimming your part ?

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precaution when trimming your part ?

precaution when trimming your part ?

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Jess8bit	Jess8bit posted 12 Years Ago HOT Topic Details
Group: Forum Members Posts: 133, Visits: 566	Hi guys, Do you take any particular precaution when you trim your part with your Dremel ? How do you protect the surface from scratches that may occur during the trimming ? I've had this problem : the srface was nice after demolding. After triiming the part, I've jad the bad surprise of observing many scratches and holes in the surface. My assumption is that I made the scratches myself simply by holding the part with my hand (with gloves on) and handling it durng the process (maybe because of carbone dust ?). Hence the question. I'm thinking about covering the surface with a plastic film hold by masking tape all around the part edges. What do you think ? thank you !!
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fgayford	fgayford posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 433, Visits: 1.2K	It almost looks like the epoxy is not cured to a hard state and the sanding dust is fusing into the soft surface?
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Jess8bit	Jess8bit posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 133, Visits: 566	fgayford (05/06/2013) It almost looks like the epoxy is not cured to a hard state and the sanding dust is fusing into the soft surface? It's a interesting guess Fred. And Yet I left the part cured for 24hrs @20°C before demolding. Maybe I should wait for 36 hrs to be sure and eliminate this hypothesis. here's a detail :
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CarbonMike	CarbonMike posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 31, Visits: 45	fgayford (05/06/2013) It almost looks like the epoxy is not cured to a hard state and the sanding dust is fusing into the soft surface? This without a doubt. I am a composite trimmer/fitter/laminator by trade, and have seen this happen many many times on virgin parts.
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Jess8bit	Jess8bit posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 133, Visits: 566	CarbonMike (23/06/2013) fgayford (05/06/2013) It almost looks like the epoxy is not cured to a hard state and the sanding dust is fusing into the soft surface? This without a doubt. I am a composite trimmer/fitter/laminator by trade, and have seen this happen many many times on virgin parts. Thank you CarbonMike What I do now is I wait for 48hrs+ before demolding. What I could try is some post curing to reduc this delay, I guess.
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precaution when trimming your part ?

Jess8bit - 12 Years Ago

Unless dremel hit the surface of the item I don't see any reasonhow just holding the piece the...

NikCFC - 12 Years Ago

well, no, it was not the Dremel, I did not hit the surface with the tool, but, does the carbon dust...

Jess8bit - 12 Years Ago

It almost looks like the epoxy is not cured to a hard state and the sanding dust is fusing into the...

fgayford - 12 Years Ago

[quote][b]fgayford (05/06/2013)[/b][hr]It almost looks like the epoxy is not cured to a hard state...

Jess8bit - 12 Years Ago

[quote][b]fgayford (05/06/2013)[/b][hr]It almost looks like the epoxy is not cured to a hard state...

CarbonMike - 12 Years Ago

[quote][b]CarbonMike (23/06/2013)[/b][hr][quote][b]fgayford (05/06/2013)[/b][hr]It almost looks like...

Jess8bit - 12 Years Ago

[quote][b]Jess8bit (05/06/2013)[/b][hr]well, no, it was not the Dremel, I did not hit the surface...

carboncactus - 12 Years Ago

[quote][b]carboncactus (05/06/2013)[/b][hr] The epoxy layer is going to be very tough. If you...

Jess8bit - 12 Years Ago

And whats wrong with this forum? it keeps putting comments INSIDE the quote! :angry:

carboncactus - 12 Years Ago

same problem with quotes by the way ;)

Jess8bit - 12 Years Ago

Looking at that last picture....... Take a heat gun to the surface for a couple of minutes. I have...

carboncactus - 12 Years Ago

I would go for the same theory as fred... I mostly wait 2 days before sanding epoxy... mostly I even...

matthieutje65 - 12 Years Ago

[quote][b]matthieutje65 (05/06/2013)[/b][hr]I would go for the same theory as fred... I mostly wait...

Jess8bit - 12 Years Ago

[quote][b]carboncactus (05/06/2013)[/b][hr]Looking at that last picture....... Take a heat gun to...

fgayford - 12 Years Ago

[quote][b]fgayford (14/06/2013)[/b][hr][quote][b]carboncactus (05/06/2013)[/b][hr]Looking at that...

Jess8bit - 12 Years Ago

Your vacuum was good, as there is no pinholes. Unless vacuum was lost after gellation Does the...

carboncactus - 12 Years Ago

[quote][b]carboncactus (14/06/2013)[/b][hr]Your vacuum was good, as there is no pinholes. Unless...

Jess8bit - 12 Years Ago

No the heat gun trick is only for uncured epoxy laminates. Get a smackhead needle on eBay, lay the...

carboncactus - 12 Years Ago

Did you use any spray adhesive,I have seen this on similar parts if so can be sanded and clear...

Shaneer22 - 12 Years Ago

[quote][b]Shaneer22 (05/06/2013)[/b][hr]Did you use any spray adhesive,I have seen this on similar...

Jess8bit - 12 Years Ago

Sounds like the sanding dust is showing up defects or your parts could do with a little longer to...

Warren (Staff) - 12 Years Ago

All right Warren, I'll pay attention to the temperature, and especially I will leave the part to...

Jess8bit - 12 Years Ago

Ok so this time I've added sprayed GC50 gel coat, and waited for 2 days before demolding (no post...

Jess8bit - 12 Years Ago

Do it the other way round. When the resin reaches the vac outlet and all the cloth is wet with resin...

wozza - 12 Years Ago

But why can't I find this by myself ?? Oh, I know, because YOU're the boss ! ;) I'll try this...

Jess8bit - 12 Years Ago

Ha Ha trust me I have learnt the hard way :crying:

wozza - 12 Years Ago

Have you tested your vacuum pump to see if it pulls a bar? And did you do a drop test? I can't...

carboncactus - 12 Years Ago

[quote][b]carboncactus (10/06/2013)[/b][hr]Have you tested your vacuum pump to see if it pulls a...

Jess8bit - 12 Years Ago

Test your pump by plugging it straight to your gauge. Yea, the bubbles are there because they are...

carboncactus - 12 Years Ago

yeah, I can only imagnie. thanks for sharing :) (@ warren)

Jess8bit - 12 Years Ago

Yeah, the tiny bubbles I see are stuck to the tows. Sorry if I get you wrong but, what you're...

Jess8bit - 12 Years Ago

No sorry, I was talking about your first part, the one you didn't use GC50 on. Degrease it and watch...

carboncactus - 12 Years Ago

[quote][b]Jess8bit (11/06/2013)[/b][hr]Yeah, the tiny bubbles I see are stuck to the tows. Sorry...

wozza - 12 Years Ago

It's crystal clear now :D

Jess8bit - 12 Years Ago

I do trust you. :D last time, what I did was probably stupid : I first sprayed a layer of GC50....

Jess8bit - 12 Years Ago

If you want a perfect looking part then leave the resin feed line open as I suggested. If you want...

wozza - 12 Years Ago

Copy that ! :) what is wrong with the double coating ? delamination ? the two coats can't bind so...

Jess8bit - 12 Years Ago

[quote][b]Jess8bit (11/06/2013)[/b][hr]Copy that ! :) what is wrong with the double coating ?...

wozza - 12 Years Ago

That really makes sense. I did not yet touch the pressure tuning knob on the gun. I only set the...

Jess8bit - 12 Years Ago

[quote][b]Jess8bit (11/06/2013)[/b][hr]That really makes sense. I did not yet touch the pressure...

wozza - 12 Years Ago

The spray seems strong to me (almost too much I'd say, but only a feeling though). My compressor is...

Jess8bit - 12 Years Ago

Not easy to tell from those pictures but you dont' appear to be a million miles away. The "blobs"...

wozza - 12 Years Ago

^^ yeah, those are very valuable tricks, I really appreciate you sharing those, thank you !!!...

Jess8bit - 12 Years Ago

No problem I was only joking, happy to help. Carbon is expensive and given the time element it can...

wozza - 12 Years Ago

mmm, 'm bit disappointed about my compressor, thought it was well dimensionned, but it has the...

Jess8bit - 12 Years Ago

Your compressor may well be ok for a bonnet? just make sure you only spray a small area at a time,...

wozza - 12 Years Ago

Ok, I see what you mean; thanks Warren :)

Jess8bit - 12 Years Ago

Ok so now I have a good surface finish, At least, no bubbles anymore (I let the resin flow some time...

Jess8bit - 12 Years Ago

[quote][b]Jess8bit (14/06/2013)[/b][hr]Ok so now I have a good surface finish, At least, no bubbles...

wozza - 12 Years Ago

Dr House party ^^

Jess8bit - 12 Years Ago

Thank you Warren for your suppor :) In this case I assure you it is not a bridging problem, the...

Jess8bit - 12 Years Ago

[quote][b]Jess8bit (16/06/2013)[/b][hr]Thank you Warren for your suppor :) In this case I assure...

wozza - 12 Years Ago

I use 3M super spray 77. Not perfect I know... It's the only one I can find :( (SprayZ still...

Jess8bit - 12 Years Ago

Ok 24 hours for the GC50 is ok but no longer ;) Ditch (stop using ) the spray tack. It is very...

wozza - 12 Years Ago

mmmm you're right, although I'm really carefull with applying a very light spray (knowing it might...

Jess8bit - 12 Years Ago

Unless the part is really complicated with lots of recesses and steep sides etc you should not...

wozza - 12 Years Ago

yep, should do that as well. It's a kind of (bad) habit I have, like if I was working with prepreg...

Jess8bit - 12 Years Ago

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