Spackle in lieu of Q Cell in a pinch...

Hi all,

I need to repair a ding that took a little bit out of the foam, maybe dime-size and 1/8" deep for reference. I rinsed the salt water off, let it dry several hours (maybe not long enough…), sanded it down including a surrounding margin with 80 grit by hand, and then decided to try filling in the hole in the foam with some “Fast n Final” lightweight spackle since I have no Q Cell on hand. I’ve let it cure for 24 hours now, and while it’s dry, it has some give (similar to I don’t know, a stale marshmallow), as though it’s not entirely flush to the underlying foam. Can this spackle decision be saved and glassed over? Or, should I attempt to remove it and just get myself to the surf shop asap for some q cell and start over? (The archives yielded plenty of skillfull uses of spackle but I couldn’t find anything identical to this ding repair query-- perhaps telling in itself.) Thanks in advance; appreciate the opportunity to learn from you all.

Doesn’t sound good. Hate to send you to the store for such a small repair. Maybe you could clean it out and fill it with a little foam plug from a scrap of foam? On the other hand, you should always keep a little thickener handy for just this reason, so maybe a trip to the store would be just the thing.

You didn’t exactly say, but your comment reads as if you either used pre-mixed spackle or mixed it yourself with water.   If so, I wouldn’t rely on that for a ding repair.   Seep a little moisture and it’s over.   

I don’t know what the answer is with spackle+resin, but I do know people have used a number of different materials for small fills. Talcum power, sugar, sawdust, etc.   Mix with resin for stability.  Some of the others might know about whether spackle+resin will work.    

One way to find out is to mix a small batch on the side and see how it sands.       

Well is it lightweight spackle? Like many use as eps foam filler. If so you can soak it with thinned epoxy then lam over with glass, it can work if not a big surface. 

Thanks all-- it is premixed lightweight spackle. It sounds like I’d better bite the bullet and get some Q Cell. Is it alright to just sand the spackle out, or what is the best way to remove it and prepare the site for a proper repair? I do have some acetone on hand for clean up. Thanks!

I’ve used both baby powder and flour (the cooking kind) mixed with resin.  Works fine.  

Q-cell  for ding repair.  If you have already filled it with Spackle and you are 100% sure it is dry to the core; sand it and glass over it.  Small dings filled with Spackle can be okay, but not recommended.  In your case it’s probably not worth digging it out.

Not to be contrarian, but I have used Fast N Final to repair a dinged blank before glassing, and couldn’t tell that there were any ill effects.  In my case, it was in a non-critical area on the bottom, so wasn’t gonna be subjected to any meaningful loads.  In that case, it was a Clark blank with polyester resin.  I couldn’t even tell where the spot was when it was all done.  Pretty sure I’ve heard of others doing the same in certain circumstances. 

Having said that, go with what makes you feel best.  But I wouldn’t sweat it if you can’t get every trace of spackle out of the hole.  The strength of the repair comes primarily from the glassing you do over it.

I have mentioned before that after Clark Foam closed, I accessed several blanks from Argentina(I think).  Eiova Foam(aka Buckshot Blanks).  I remember remarking to my glasser when I dropped of a few shaped blanks for glassing that the blanks were more Spackle than Foam. Yes I have also used Spackle for a variety of things related to Surfboards.  But when I fix a ding with Q-cell and do it properly, I never have any doubt that it will hold.

My guess is your spackle isn’t dry all the way through. I’ve tried to fill stuff with spackle and never got it to dry completely before I got fed up and scraped it off. I suspect it would eventually dry but it would take days. So, I’d either suggest allowing more dry time or using something different to fill it. I’m not sure if joint compound dries faster or not but I know it’s meant to fill larger gaps. It may not be as bright white but you can worry about color once it’s filled and dry. At that point though you might as well go buy the right stuff.

Update: Spackle came right out. Hole was slightly bigger/deeper than I’d remember & described here. Got some Q-Cel at a premium from my local shop, mixed it up with resin to toothpaste consistency, filled the hole. It’s fully cured thankfully & soon I’ll sand it down and complete the ding repair. To anyone reading this down the line, hope my initial misstep is of use! Just get the right stuff from the get-go.

Dime sized, 1/8" deep. I think you will be fine with the spackle glassed over. I’ve used spackle for several repairs. It will be a little soft, but a dime sized patch is not going to be a problem.
In the past, I’ve saved the sanded foam and sanded wood in a ziplock bag. I mixed that with resin to make a filler. These days, I buy Aerosil and Qcell, and I take remnant pieces of glass and cut it up into tiny shreds, as small as I can with scissors. Then I make a slurry with resin and use that as a fill. I figure that is as close to milled fibers as I can get.
Way back in the 70s, I’d just fill the hole with resin, no glass over that. It wasn’t the best repair, but I could be back in the water the same day.