Newbie with a few questions about fabrication.

[system]

First of all, I’d like to thank all the guys on the forum. I’ve been trolling here and Racingcomposites for the past few months and have gotten invaluable knowledge and data regarding carbon fabrication. I’d been interested in this for the longest time, and had been meaning to make something, but it is a pretty daunting task for a complete beginner. I operate a website selling aftermarket parts for cars, and have been doing so for the past few years, and I’ve also sold a number of carbon products, so I had a general idea of how things are made, but in any case, this site has been very helpful.

Okay, onto the questions.

I’ve been making a few molds, as well as products, in the past couple of months, and with a little more practice, I intend to make sellable parts. I just had a few hiccups along the way.

I use chromed plasic parts to use as plugs for molds, and the mold surface has been very good, so good that I have not had to even touch the mold surface before producing parts. The mold surface is very shiny right when I pull the plug off.

I’ve tried various methods of fabrication.

Here’s a big question. When I just use infusion with no surface coat, I get an imprint of the carbon pattern right on the mold surface. I tried this method because for certain parts, I wanted the dry-carbon look. Is this what is called print through? Is there anything I can do to prevent this? I tried to remove the imprints using wax, with no success. Will acetone remove the imprints? Also, if I don’t remove the imprints, is that okay?

Also, when I put on a clear gel coat, let dry to the tacky stage, and then go with either regular bagging or infusion, when I pull the part out of the mold, it looks fine, with no surface pinholes, but when I spray clear coat, pinholes show up. I spray the clear coat on pretty thick, but the pinholes don’t go away, and the pinholes eventually show up as dents. What am I doing wrong? Should I spray thin coats of clear multiple times? I’m thinking that this won’t help much as clear coat usually won’t go into the pinholes.

By the way, for now, I am making small parts, using a vacuum sealer that you use in a kitchen. I think it doesn’t pull enough vacuum for certain applications, but it seems to be okay for some parts. In some cases, I see air bubbles between the weave. Is this because the vacuum isn’t strong enough?

If anyone can help me, that would be great.

I’ll try to post some pics of some molds that I’ve made so far.

[riff42]

Here’s a big question. When I just use infusion with no surface coat, I get an imprint of the carbon pattern right on the mold surface. I tried this method because for certain parts, I wanted the dry-carbon look. Is this what is called print through? Is there anything I can do to prevent this? I tried to remove the imprints using wax, with no success. Will acetone remove the imprints? Also, if I don’t remove the imprints, is that okay?

Only one I can answer I think.
It might be that the weave of the fabric is leaving behind epoxy as you pull the part off. I’ve had epoxy leave itself on the mold before, which transfered onto the next piece. You might have to repolish the surface. OR, you might be able to just do another piece, and see if it stays. Maybe a quick gelcoated piece with glass, and see if the gelcoat lifts off the “weave look” epoxy.

if it IS actually an imprint into your mold…odd, but you will have to resurface it then.

[system]

No one else can help me with these issues?

[Werksberg]

Does the mold have the cloth print in the gel coat?

When you made the mold, did you only use cloth or mat (surfacing veil) as the first layer after the gel coat mold surface?

[system]

If you are getting print through when you dont use any surface coat, then why not try applying a surface coat of some sort on your mould surface first?

[uber_motos]

I think your pinholes may be caused by contaminates on the surface of your part. Something that the clear coat doesn’t like to stick to. What kind of release agent are you using in your mold? This will be transfered to the part and it you don’t get it all off, you’ll have problems with pinholes when you apply the clear.

[george_grat]

Also, when I put on a clear gel coat, let dry to the tacky stage, and then go with either regular bagging or infusion, when I pull the part out of the mold, it looks fine, with no surface pinholes, but when I spray clear coat, pinholes show up. I spray the clear coat on pretty thick, but the pinholes don’t go away, and the pinholes eventually show up as dents. What am I doing wrong? Should I spray thin coats of clear multiple times? I’m thinking that this won’t help much as clear coat usually won’t go into the pinholes.
.

When I start I have the same problem. How I solve it? I stop to spray the geal coat. I use a simple paintbrush with a lot of geal coat to corners and all the area of the mold (not too much). First you brush in horizontal direction, wait for 2 min and then brush at vertical direction. When is cure then I make infusion, with this way bye bye pinholes. Now I have forget them.