Tips/Advice for glassing, sanding

General Discussion
1

I’ve done about 12 to 15 boards now but I still seem to have the same problems. I’ve done a search and haven’t really found anything to my problems.

When I sand my boards I still have scratches even after sanding to higher grits, I get weave exposed (cause of sanding too much I guess), have dips or shinny spots, and now then I sand the leash plug and fin plugs there must of been air gaps because there is gaps that I have to reapply some resin.

So I will go over my steps in glassing and sanding, any advice or tell me if I’m doing something wrong.

Start but putting a tape line down (to cut the excess fiberglass away). Turn board over and lay cloth on, cut to size the laminate, using UV curing resin. Let the board cure, flip over and cut excess fiberglass away at the tape. Sand the rails and cutlap with sandpaper. Turn board and repeat for the deck. When cured flip over and cut excess away, sand. I start my hotcoat with the deck first. Mix resin and hardener, apply by pouring the resin on the deck, work it out to the rails, do a cross stroke one way on the board then the other way on the board, one final lite walkout form the middle to the rails, then I walk around the rails. Let it harden, sand the excess that dripped to the bottom. Flip the board and do the bottom. I put a tape line around the rails, then repeat as I did the deck. After it cures I do the leash plug, mixing resin, pigment, and filler. I try to get it thick alsmost like a paste. Pour it in the hole (that I drilled or for it) spreading it on the sides and filling the hole about half way. I put the plug in and rotate it to try to work any bubbles out. I tape it down , and come back and removed the tape and the tape I placed on the outside of the plug hole, when the resin has setup but not fully cured. I follow the instructions for the FCS fin plugs, try to make sure that I’ve used enough filler. The last board I did I mixed 150 ml of resin with black pigment and 15ml of filler (that should be the 10% the instructions say).

Now on to sanding. I start with a 80 grit to take down any high points and the leash plug and fin plugs using a firm backing pad. Then I move to 120 grit with a med pad. I work from the tail to the nose and back down to the tail. Then I go form the tail to the nose but instead of going along the length of the board, I go from the stringer to the rail, and then from the nose to the tail. The I do the same with 220 grit, now doing the rails also, I hit them quick with the sander to take it down. Then finish the rails by hand. Thats normally where I stop.

I continue to see, shinny spots where it seems the resin is lower than around it (not just one or two spots, but quite a few spots), then I get the weave exposed because I’m trying to sand those shinny spots. I’m not sure why I’m getting the air gaps and I still see the scratches formt eh 80 grit. Is this normal? The only way to fix it that I see is putting on another resin layer and sanding it again. Should I do that then sand it starting from 220 to working up to 600 grit? Also I heard a little about speed finishes, is that a better way to go? Would I just spray that on after I sand it to 220?

Any tips advice would be great, this has been driving me nuts, cause just when I think I got it, I don’t. Thanks for any advice.

2

That sounds pritty much the way I do things, as far as the scratches go try leaving striaght edges on your pad, so it looks like an octagon and not a circle.

also sounds like maybe you sanding for too long or too heavy at the 80 stage or not enough at the 120. each sussessive grit should completely remove the scratches from the prev.

just knock down any tits or drips with the 80 and one light pass other the deck and bottom leave the rails then move on the the 120 use a softer pad.

try putting pen matkes on the board so you can tell were you’ve already been ith the sander.

You’ll never get though low spots down without hitting weave if you use the sander, leave them alone with the sander and get them by hand.

3

A lot of views, no one has had these problems or has advice on not getting them?

4

thanks, woody. Any advice thoughts about speed finishes, do you use it?

5

Do you buy your fiberglass on a roll, or all crumpled in a bag? If on a roll, has it been re-rolled? Sometimes it’s not the lamination, but some pre f-up fiberglass. Sometimes you’ll lay down a completely smooth lamination, just to find out that it’s got these corn rows in the fiberglass. What kind of glass are you using? S, E, Warp? they all have a slightly different work schedule.

But if your getting dips in your lamination and hot coat, that tells me a few things. 1) your not pulling off enough resin during the lamination process. There should be no shiny or puddle spots, just matte finished cloth, no fiberglass boogers, all strings should be flipped back onto the fiberglass, no runners out on to the foam. Use even pressure with the squeegee. 2) your not preping the lamination good enough before the hotcoat. Get the lamination flat and smooth, corners, nose and laps should be pretty much looking smooth / flat. Cut them down with the surform. Make sure you cut the glass with a sharp surform. Sand paper will smash the glass, and leave you with whitties or foggy glass. 3) Your putting too much hotcoat on. You might be getting slabbing & puddling. The hotcoat is just a filler for the weave, it’s just there to fill the pinholes. Don’t use it for a leveling. All it will do is add weight, it has no strength value. Get your flatness from the prep work, pre hot coat 4) Sand the hell out of the hotcoat. 5) When you do sand, make sure your using the right kind of sand backer for the job. Hard for flats, medium for rails, soft for the lighter grits & swirl removal. 6) Hopefully your flats are smooth, and the sanding is all about the lap areas. When sanding the lap areas, make sure you use long flat passes, don’t grind on any specific area. All this will do is give you a gradual dip, instead if a smaller dip…it will still be a dip. remember all the flattness comes from the prep work.

So what have we learned here? Answer: It’s all in the prep work. If you get to the gloss and the board is still wobbly and weave showing, guess what…its going to be wobbly and exposed. It all comes from the lamination…step one. Screw up step one, and all the rest of the steps are going to be more and more difficult as the steps progress. Once you lay down the gloss, it should be all about polishing out, not resin removal.

Keep trying, it will come. Hope this helped?

1 Like
6

Great advice Jay-

I needed that, what with a new 9’8" coming up in the next couple weeks…It’s easy to forget. Thanks.

7

Thanks Jay! . . . explained why my hot went bad . . . and looking back . . . i did screw up some parts of the lam.

8

ah yes, cloth folded up in a bag. That’s my story. I’ve been purchasing cloth from Thayercraft. I use them because they all sort of light weight cloth. I used 2.6, 2.74 (bad stuff, very stiff, wouldn’t stay down on the rail) and 3.2. I was wondering about the folds. Is there a way to get them out?

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thanks, I’m using E glass warp. I’m sure that I’m leaving to much resin in during the lam, I always see “puddles”. I’m sure again that I’m using to much hotcoat. The last board I did was a 6’3" fish design and I used almost a quart for the hotcoat on the deck. Did that because I thought I was using too little and thats why I getting weave exposed, besides sanding to much. So on my next board I will be sure to work more resin out during the lam, use less hotcoat, and I guess what your saying is surform the whole board, before the the hotcoat. Thanks I can always count on the guys here to give a hand.

Now I’ve seen somethings on here about the speed finish, any thoughts on that? Would it be better to sand the board to 220 then apply another very lite coat of hotcoat resin, then sand it starting at 320 finishing at 600. Or after the sanding to 220 putting a speed finish on? I know nothing about the speed finish, so if you have anyhting about that type slowly.

10

Personally I like to add a gloss coat, then sand it down to the appropriate finish. If I do something out of a can, like a laquer or rattle can, then I use UPOL clear coat. Or some other product that is a 2 part LP type product.

Warp is a bit harder to laminate than the regular E or S type cloth. All those fibers running the length of the board, and not as many running side to side. That cloth tends to leave ridges running rail to rail, and theres nothing you can do about it.

Also getting your fiberglass folded up in a plastic bag is way bad. Especially if your looking to so some kind of dark color tint. if you can’t buy it on a roll. Buy it from some place that at least sells it to you rolled up and wrapped in brown paper. If you start using tighter weaves like Impact glass, the glass will be ruined if it’s all folded up.

11

Only use the surform for the knockdown of lapovers, zits, and stringy thingies. Really you should be getting you laminations tight enough to where your only using it on the nose folds, the 2 tail corner folds. and any glass stringy thingy flip back overs.

Slightly push any ridges of glass into the foam with your fingernail so the next layer of glass fits smooth and flush. If it’s glass over glass, like on the bottom of the board, this is where I really slice away on the laps. I really try to get these as smooth as possible before hotcoating. Once again it’s all in the prep work, that makes the next step go easy.

12

thanks resinhead, I do buy it on the roll. I get what your saying about the surform now. I’ve been buying Warplite warp E-glass. But I think the place that I buy it from also has a twisted(?) fiberglass cloth, would that be better. And about that spray, you said you use UPOL where do you get that at? I would even know where to start and it there something I should look for in it or is it just one product? Thanks again.

13

I get it at automotive paint supply places. You can get it in a rattle can, or you can buy it in pints in a A / B mix. its cynaide based so be careful.

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Quote:
Also getting your fiberglass folded up in a plastic bag is way bad. Especially if your looking to so some kind of dark color tint. if you can't buy it on a roll. Buy it from some place that at least sells it to you rolled up and wrapped in brown paper. If you start using tighter weaves like Impact glass, the glass will be ruined if it's all folded up.

Oh, now you tell me! Yeah, I had some problems with that 2.74 oz frm Thayercraft. It was stiff and wouldn’t sit on the rails. I had to cut reliefs every 6" or so. Also, now that I am prepping for the fins I noticed slight ridges (the folds?!). I’m hoping the hot coat will get rid of them. Being such thin glass I can’t sand into the weave too much.

On the other hand the 3.2 oz (also folded up) had zero problems.

15

hi resinhead

once you have put in your hotcoat and start sanding, you never hit the weave, right?

you put enough hotcoat in to sand the whole board to a level surface, or do you add a 2nd hotcoat?

Thanks

16 
Howzit Wouter, Another way is to sweet coat the areas that are prone to sand throughs before hot coating.Aloha,Kokua
17

That has been great info, I’ve looked over it many times. One last question, how do you guys make your relief cuts for the nose and tail, Mine never come out good. Any tips on that.

18

Howzit revolution, I do 1 cut at the tip of the nose and depending on what kind of tail I do a cut where ever there is a corner or athe tip if it’s a pintail. The trick is in the wrap and how you squeegee the glass. Aloha,Kokua

19

for the nose I’ve tried doing a “V” cut but then it seems like the tip point of the nose is not covered. I’ve also tried cutting two little sections at the nose. So that there is some on the tip to over lap. But both ways it seems like I have some of the board exposed. So what I’ve been doing is on way on the botttom and the other way on the deck. If its all about how you wrap it, any tips on that?

20

Howzit revolution, Just make 1 cut at the tip of the nose and overlap, the only time I do a vee cut is with tints and the cut should be precise so the ends meet together. The trick to squeegeeing is as you wrap the nose you need to slightly rotate the nose edge of the squeegee inwards which changes the weave from a square weave to diagonal as it wraps. Not sure if this is a good explaination but hope it helps. It’s all in the technique which comes with practice, good luck.Aloha,Kokua