Will I ever sand without burn-throughs?

[img_assist|nid=1048912|title=lap burnthroughs|desc=|link=none|align=left|width=75|height=100]I know I am in the very early stages of the game (7 boards shaped/glassed), but I am wondering how many boards did it take you seasoned-folks before you were able to consistently sand your hot-coats without burn-throughs?

I have been getting progressively better at sanding, and my burns are now pretty much isolated to the lap-line, but I still get enough burns that I have had to do a second hot/glosscoat regardless of whether I wanted one or not. The attached photo was a pretty easy fix since I pinlined and gloss/polished.

 

I use a decent Black and Decker 6-Speed polisher/sander (0-3000) with a soft yellow powerpad and run it on 3 on the flats and 2 around the laps/rails (100 grit). I also try to sand/smooth the laps (with a hard block and 60 grit) after each lam (perhaps I am taking this step too lightly?). I even “rolled” the laps with the last 3 boards I did with Kwick Kick (all my glassjobs have been RR).

Anyway, I’m just wondering if it’s just a question of time (many more boards) or if there are some techniques I could be using to speed up the learning curve.

Thanks

My first thought/question is: When you say “run it on… 3/2,” I’m assuming you mean you set your sander at a speed and leave it there.  If so, that is a problem to me.

I use the “hit the trigger, let off, then start the sanding,” some times referred to, I think, as “feathering.”  You can do it over and over as  you go.   Also,  move more/don’t stay on one spot very long… It gets hot, hot enough to “F” things up.

Yes. I set my sander on 3 or 2 and leave it there. Not much “pulsing” or “feathering” but I will try that next time. I am, however, very careful about keeping the sander moving at all times. Thanks.

I looked at your first post again - Maybe you are not taking the first edge down enough.  I think most folk try to get it pretty much flat and smooth before lamming over the edge.

 

I think that will be my next area of focus: really trying to smooth down the laps flush to the foam before lamming the deck. I assume I should also do the same with the bottom laps before hot-coating? I noticed Greg Loehr uses a pneumatic disc sander to do this on his DVD. I don’t have any pneumatic tools. Is there a good substitute (regular sander) or should I invest in pneumatic?

Regular sander is fine.  You might find a “random” orbital type to come in handy  - Flat is good for getting rid of high spots… If you are careful. 

do yourself a favor and read all of lokbox’s posts…twice

http://www2.swaylocks.com/forums/what-am-i-doing-wrongsanding-final-coating

I’ve found that if you don’t want any sandthroughs, make sure everything stays nice and level starting at square one…that, and, no power tools and heavy grits around noses, tails or rails…do it by hand.

a little bit of hand sanding is better than 2 days of epoxy patching and fairing.

    Howzit Jamie, Do your self a favor and buy a Ferro soft pad for rails, 6" or 8" both willwork.Aloha,Kokua

hi jamie its called a sharp surform blade, and you do it when the resin is kicked but not “sanding hard” . it takes about 5  minutes to take down a lap before fill coating

also its likely a trap for young players is resin rich laps. when laminating you need to go round the laps twice to get all the excess out.

but at the end of the day the board is not properly sealed unless it gets a third coat of thin resin

this was industry standard for a very long time and abandoned in the 90s by big manufactures who are now relizing chinese boards of the same weight with finish coats, last longer.  they will soon go broke unless they offer better quality boards

Thanks everyone for the tips. Kokua, do you mean one of these?

 

Jamie,

 

A good sand job starts with a good lamination and hotcoat.  A good tight lamination that is preped so it's flat and smooth will yield a hotcoat that looks pretty close to a gloss job.   If you get those results then you don't have to chase grinding down boogers, glass spikes and lumps.  Give yourself a fighting chance, start off with a smooth surface and things will move along better.  Nothing worse that trying to sand a board with bubbles, dry laminations, boogers, cutlap edges that were not pressed into the foam before 2nd layer of glass etc..

There is no subsitution for learning and just doing it. Your sanding will get better....your glassing will get better....your shaping will get better.

 

Keep at it.

Silly,

You just explained away some of my frustration...I've read about using the surform on laps before but never picked up on that it should be done before it was fully kicked.  unfortunately it is too late for my current victim uuum i mean board Thanks Chris

no worries. the surform must be clean and sharp. i use the same one for the one job it costs 10$

i have die grinders and small grinders and have done some messy nose and tail laps with grinders, but find a tight clean lam will be clean in no time at all with a surform by the time my compressor has even filled its tank,

you bend the surform slightly. angle it and go kinda lengthwize on an angle. i can do it on deckside 4oz wothout hitting the foam

 

i agree with everything resinhead says except “cutlap edges that were not pressed into the foam before 2nd layer of glass etc…”

if you have to do that then you are either cutting at the wrong time or wrong method.

So, if I am to take Silly’s advice on the “sanded finish” thread that it is pretty much unavoidable and undesirable to not have at least some burn-throughs sanding a hot coat, then perhaps I shouldn’t worry too much about it the perfect burn-through-less hot coat. I have been able to get good results and no burn-throughs once I apply and fine sand a thin second hot coat (gloss coat). Maybe I should put more effort into getting nice smooth pinlines…

you can use a lot of resin on your hot coat and avoid it, but i prefer to use minimal resin for hot coat and do another coat . its a win win/win

there is far less sanding if your laps are clean and down and more acurate with less likely chance of sandthroughs

the places you will expose weave the most where sanding is around the laps in the tail and nose areas and hard edges in tail. these areas are the most likey areas to pinhole on the rail. a really good glass job takes about 15 to 20 minutes to sand

you know if you want a really clean durable and pretty board its best to take the extra steps

 

Sand throughs are pretty much a sign that you haven’t got enough filler on there to begin with, as well as excess bumps easily fixed with a surform as others have wisely mentioned.

When you’re hot coating/filler coating, one side should have been taken round to the other side and over the lap,

Bottom to deck is usually first

then as soon as it has kicked sufficiently to flip it, do the other side and take it all the way round over the lap to past where the deck lap went to the bottom.

Catching it just after it has kicked and before the wax has fully risen means both coats wil adhere to one another

Don’t be to overly concrened with drips or imperfection, just aim for even coverage past the laps.

You should be able to get 90% of the rails done with the sander, dropping it down and angling it vertically as you take little lines. Keep it moving quickly and avoid the nose and tail extremities.

If you keep the pad contact surface flat and centered, it’s easier to handle, the centre of the pad is smaller diameter and thus moving slower and also less likely cut too quickly.

Aiming to eliminate 100% of the shiny spots with the sander is optimistic on all but the best hot coat, so don’t chase stubborn ones and go too far. Best solution is a used pad folded in half and use palm pressure for the last of it.

Very good ear protection for other than the obvious reason can alleviate the stress that loud spinning electric motors can induce.

If you’re intimidated by the sander and concerned about sand throughs, that what you will get, it’s a confidence trick.

when you do your bottom lam, baste the foam next to your lap line with some resin, and a 1-2 inch brush. let it dry, and surform or grind away with a small orbital sander unitl flush with foam. there should never be a bump where lapline was. this will prevent the foam from be ripped into. then lam deck and sand or surform lap line flush. apply hotcoat as normal, and hand sand the rails to prevent burnthroughs.

as for your situation right now, sand with120 or 100 until entire board is smooth, the apply another hotcoat, this time thinner, and sand to 320.

Board is done and my friend just walked out the door with it, stoked. I sanded the hotcoat to 100, then added the glosscoat (all RR KK Epoxy). Sanded the gloss: 320, 400, 600, 800, 1000, 1500, 2000 (600-2000 were by hand, wet). Compounded with 3M Perfect It and Polished with 3M Swirl Mark Remover. No burn-through problems. Turned out pretty nice. Thanks to everyone so far for the tips. I think I just need to take more time getting the laps flush in the future.

 

If that was your first KK, you will have found that KK alone is a big help in avoiding sand throughs.  KK just stays were you put it, instead of dripping off.  Were the troubles you were having from Poly or another epoxy resin?

    Howzit Jamie, Those are the ones and the supersoft is the one for doing rails. But no matter what kind of pad you use there is no substitution for time using your grinder. Thee more you sand the betteryou will get. Aloha,Kokua