Cloth and sanding resin

General Discussion
1

Hi there, guys. 

I am a long time lurker on this forum but I had never needed to register until recently. I have tried opening old posts in the archives and I just get a “post not found” error. I have tried my best to search for answers but I’m not having luck. What I’d like to know has been discussed ad nauseam here so I apologise in advance. I’d just like a couple of definitive answers. 

 

I have always used “general purpose” polyester resin (sanding resin) to repair dings and this includes dings that require cloth. I have had good results but I’ve been oblivious to the fact that people lay cloth, even on dings, with laminating resin. I’d really like to know why. I understand the inclusion of styrene wax in resin to make sanding possible but why should one not lay cloth in a ding with sanding resin? 

 

 

 

For some further context, there are no ding repair people in my immediate area and dude to the pandemic, I can no longer do my regular work. I’d like to start repairing boards professionally but before I open my doors, I’d like to be confident fixing all things - creases, snaps, holes and I’d like to learn some of the tricks of the trade so all advice is welcome. 

 

Thanks

2

Lam resin stay tacky after cure so hot coat chemicaly stick to it. If you lam with sanding resin you have to sand it before recoat to have a mechanical adhésion.  

3

Exactly.

4

It might be worth your while to spend some time at https://boardlady.com

5

Exactly as lemat stated.  It stays tacky.  So it sticks better to the surface it is applied to and subsequent layers of cloth or resin are sure to stick.   When you or I or anyone repair a ding for someone, we might never see that board and repair again.  So we have no idea whether or not the repair held up.  I have seen repairs done with sanding resin only.  Usually the resin around the cloth/repair chips or flakes off.  Oftentimes the cloth on the resin will release from the sub service.  You will see where the cloth turns loose around the cloth edge.  If you are going to attempt to do ding repair for money, you had better learn to do it right.  Otherwise you are going to have disgruntled customers bring back boards with your ding repairs that fell apart.  Lots of Polyester ding repair video on YouTube.  While  much can be learned from the board lady, keep in mind that she works with Epoxy not Poly.  The solution to using and buying only one type of resin is to buy Polyester laminating resin(preferably Silmar 249A) and add wax solution to that resin when you need sanding resin.  Takes very little Surface Agent added to Poly lam resin to do the job.

6

PS   What you call “general purpose” resin could be anything from “Bondo” $#it resin sold at Home Depot to the “Fiberglast” resin sold at marine supply houses.  All JUNK.

7

That’s a good point, since all I use is epoxy, I never really thought about that.  But hey, if you’re going to repair boards professionally, you’re gonna have to learn to work with epoxy.  I use it even for ding repairs on poly resin boards, never had a problem.  But I’m not doing ding repair professionally. I’m just saying, if a guy wants to learn some tricks of the trade and gain confidence in handling a variety of repair situations, it might be worth their while to spend some time on the board lady’s website.

8

Her techniques and experience with epoxy are invaluable.  I was doing a lot of Epoxy repairs back a few years ago and she was the only “certified” Surftech" repair person at the time.  Couldn’t even get paint colors.  She had it locked up.

9

Buy lam resin and the wax additive. Use surfboard specific resin and not the cheap purple stuff. Color matching is easier with Silmar 249 because it has little color of its own. Using boat or car type resin will result in a less than professional repair that does not justify charging someone for.

10

Back when I was learning from someone with lots more experience, i was led to believe that saturating cloth  for dings, was always best done with lam resin, and once it was  tacky one could then paint it/ fill the weave and outside the cloth,  with sanding resin.  I was told this made for higher adhesion and more flexible ultimately stronger repairs, compared to using Sanding resin for wetting out the cloth and every subsequent stage.

 

Is this true, and if so, how much stronger is it? 

I know not.

 

Far too many do not sand enough prior to covering the ding, and then sand off most of what they laid atop, and have a fragile ding repair.

 

I use epoxy now, and while it has better adhesion to substrates, mechanical tooth is still important, and while dull sandpaper can make the surface no longer shiny, sharp new sandpaper leaves sharp valleys and mountain tops and greatly increases adhesion.

Scrub all wax/oils/contaminants from the area, before sanding. 

 

Remember, making a super strong spot on a rail, makes two weak spots just ahead of and behind that strong point.  One needs to spread the strength of a repair, and using more resin than required to saturate the cloth, and then fill the weave, is counterproductive.

 

I try to utilize the poor man’s vaccum bag method whenever possible for no/ minimal sanding post cure, but I only use epoxy, and I am not aiming to make repairs invisible to sight or feel, just strong and watertight, and I only work on my own boards, as making other surfers happy, is not something which floats my boat. 

I learned that shortly after I learned how to properly use lam and sanding resin, but occassionally need a refresher course, it seems.

11

Thank you so much to those who contributed. It’s significantly more complex than I expected. One thing is for certain, I’ll be buying laminating resin and wax tomorrow.

Thanks for linking the board lady’s website. I have a feeling I’ll spend a few hours reading through the articles. Epoxy is not so popular here but I do need to learn how to use it too and some of the other principles seem to be universal.

You guys are right, if I am going to charge for repairs, even on a small scale, I need to be proficient.

Thanks again.

12

Epoxy is needed to repair compsand boards like surftech, degree 33, global surf industries, etc.

It’s unfortunate these are being called epoxy surfboards, which is really misleading, but they use epoxy resin in the composite sandwich skin over EPS foam

13

You go the idea.  Like the old man said;  “If it’s worth doing.  It’s worth doing Right”.