How to get that smooth epoxy/fiberglass finish?

Joined
Feb 19, 2013
Likes
4,384
Location
Chico California
#1
Working on getting a smooth/glass look to my fiberglass and having a hell of a time. Do you just keep sanding and brushing [roll and tip] epoxy until it comes out smooth? Seems like I always have little divots. Any tips; on peel ply or fillers I can add to get a nice even finish with minimal sanding? I get same results with s-glass, biax, weave etc so I could use some help.


@Vumad
@Nate_D
@hink320
 

CD155MX

Squirrel!!!
Joined
Jun 10, 2006
Likes
642
Location
Moreno Valley, CA
#5
Making repairs. Also looking to redo the bottom of my blaster.
I would highly recommend looking into vacuum bagging. I've dipped my toes into the waters a bit on the last few repairs I've done and have been overwhelmed with the finish product compared to normal wet layup. It feels like cheating almost. Next step beyond that is like what @hink320 said. Infusion will yield even better results than vacuum bagging.
 
Joined
Feb 19, 2013
Likes
4,384
Location
Chico California
#6
I would highly recommend looking into vacuum bagging. I've dipped my toes into the waters a bit on the last few repairs I've done and have been overwhelmed with the finish product compared to normal wet layup. It feels like cheating almost. Next step beyond that is like what @hink320 said. Infusion will yield even better results than vacuum bagging.
You are probably right. And what better place to practice then on the bottom of a ski. :)
 
Joined
Nov 3, 2016
Likes
20
Location
Northern michigan
#8
Quinc- if you decide to do the bottom. Use three or more wide strips with the seem falling in between the center section and the chine(in the valley between). I have tried several times to do it with one piece. The problem is under heavy vacuum the fabric will separate from the low area making voids at random. If you use at least three pieces over lapped they can migrate during the process and not cause the fabric to pull away.
 

McDog

Training 'em right
Joined
Jan 14, 2007
Likes
2,186
Location
South Florida
#11
It will be a lot of supplies, equipment, and trial and error for bagging or infusion. Please post updates and write ups to let us know how it goes. The more details the better. I may tackle this someday myself.
 

hink320

Site Supporter
Joined
May 28, 2012
Likes
1,150
Location
sask, canada
#13
Ya, bagging definitely helps. If you are stuck hand laying, placing some poly or perforated release film over the glassed area before it cures seems to help smooth it out.
 
Last edited:

mike b

Michael "Mayhem" Bevacqua aka MikeyChan
Joined
Sep 3, 2012
Likes
1,007
Location
California
#14
Bagging or atleast laying peel ply and vaccum bag over top really helps smooth out the finish. Make sure to use epoxy resin which sounds like you already are as I believe the peel ply says epoxy and vylnester, not polyester. If I have that correct. I have only used with epoxy. Biggest thing is I have found pin holes when doing repairs. Not sure if this is just gases escaping and I need to practice more. I'll leave that to the experts. But the repair being bagged under or not under vaccumm is really nice and clean. Cuts down sanding time for sure.

This finish is great for the tray as a quick sand and perfect foe tued. Like I said before a good amount of pin holes you will see in the primer. I'm sure infusion lays out without pin holes but never done that on a repair.
 

Vumad

Super Hero, with a cape!
Joined
Jun 21, 2007
Likes
2,566
Location
St. Pete, FL
#15
You spray epoxy resin?
Pat at FGCI said never to spray epoxy resin.


If you are hand laying and rolling the glass it's going to get lumpy. Chop is especially bad because it move so much. Weave and cloths can stay together. They will contour to whatever is under them of course. The only thing I know of that you can do to get a perfect finish to is do body work after. Mix Talcum powder with epoxy to do this. It sands easiest. Glass microspheres sand easy and are lightest but should only be used on places like the tray because they are hollow and leave pin holes. Put on a light dusting of spray paint and then sand to see where your low spots are. Do not sand into the fibers under your filler. Finish the job with a high build primer before paint.

Sorry bud, the only easy way I know to do body work is to pay someone else to do it.
 
Joined
May 6, 2013
Likes
69
Location
Portland
#16
Like Vumad said, I recently rockered my blaster and did the best I could with my minimal experience and short time line. After the glasswork I did several fill and sand sessions with epoxy mixed with lightweight fillers. By the end I stared to get the hang of it and wasted less material. If I had an extra couple weeks I could have made it a bit smoother but I made sure to focus on the most visible areas and it turned out pretty decent.
 
Joined
Jul 30, 2015
Likes
52
Location
Sacramento Delta
#17
Ok, I have never done this, but it sounds intriguing. A Czech buddy of mine who built kayaks back when they were (and racing kayaks still are) fiberglass was in TAP Plastics the other day, and was told that you can hand lay up and then put mylar over the wet lay up then squeegee the mylar and you will (or can if done properly) get an "inside-the-mold-like" shiny finish when you peel the mylar off.

But epoxy sticks to everything! So, I think I would call TAP about this before doing it to make sure that you can actually peel off the mylar!!!
 
Last edited:
Joined
Jun 12, 2011
Likes
246
Location
Southeast
#18
The glass lays out as smooth as the surface underneath. I smooth everything out with epoxy then put two layers of 6oz down and feather that out with 80 grit
 

Vumad

Super Hero, with a cape!
Joined
Jun 21, 2007
Likes
2,566
Location
St. Pete, FL
#19
Ok, I have never done this, but it sounds intriguing. A Czech buddy of mine who built kayaks back when they were (and racing kayaks still are) fiberglass was in TAP Plastics the other day, and was told that you can hand lay up and then put mylar over the wet lay up then squeegee the mylar and you will (or can if done properly)get a shiny "inside-the-mold-like" shiny finish when you peel the mylar off.

But epoxy sticks to everything! So, I think I would call TAP about this before doing it to make sure that you can actually peel off the mylar!!!

Epoxy does not stick to everything. It doesn't stick to anything with a wax surface. It doesn't stick to visqueen and other such plastics. Vacuum bagging works because of this. Vacuum bagging uses peel ply which allows the resin to pass through to the absorbent fabric on the other side, then a plastic sheet like visqueen seals the air. Not only can you peel off the visqueen easily, without wax, but you can also peel off the peel ply and it has resin inside of it. You can also remove the epoxy part from the waxed mold.

You can get a glossy finish by covering it in plastic. I did this with my rear sponsons. I put down plastic, then glass, then plastic, then piled cinder blocks on top. I got a smooth 2-sided finish from a simple compression mold.

However the finish will only be as good as the layup. Any wrinkles in the plastic will cause blemishes in the finish. It also will not correct any blemishes causes by uneven plug or uneven fabric thickness in the layup. Remember the OP is trying to fix divits and dimples in the base fabric. Plastic will not fix those. Resin is not UV resistant so you should be prepping it for paint/primer anyway.

I have brushed on epoxy and allowed it to cure for a smooth finish. I usually use this to seal my plugs since I like to use drywall mud to build them. A few important notes.
Cheap chip brushes loose their bristles. They are an absolute MOFO to sand out. Don't use habor freight chip brushes to brush on plain epoxy (although they are great for laying up fabric). Use better quality $2-3 chip brushes so they don't loose their bristles.
I actually prefer the foam style brushes. I'm not sure if the foam brushes will hold up to poly or vinyl resins so you need to test that. I have only used it with epoxy to seal my plugs (poly and vinyl melt exposed foam).
Use a heat gun. Resin gets more viscouis when heating. This helps it lay smoother and takes out the bubbles. Just remember you will get sags on vertical surfaces. Also realize it cures exponentially faster after 70 degrees, so don't heat the pot or you wont have time to get it down.
 

Vumad

Super Hero, with a cape!
Joined
Jun 21, 2007
Likes
2,566
Location
St. Pete, FL
#20
Making repairs. Also looking to redo the bottom of my blaster.
Can you get to both sides of the repair? My on-the-part method works great on anything you can get to the inside and the outside of. I posted directions in another thread but the short of it is...

You rebuild the area out of something easy to work like drywall or plaster
Seal with epoxy
Lift a mold
Remove plug materials
Prep for glass
Wax and apply mold
Layup repair from inside. Apple a small amount of filler so you don't miss the edges etc. You can make it look more finished by putting down repair the thickness of the hull and then laying up a larger piece inside to hold it together (so you don't have a big divit inside)
This method works with vacuum bagging.
If done right, your outside finish will be ready for paint when you remove the mold (probably need a little glazing putty)

For a faster job, lift the mold from a different ski that is not damaged.
 
Top Bottom