Okay, so you have this surfboard.....and it needs
fixing...
Well, I don't do housecalls. So, this handy set of answers
to..some of..your questions. As I'm basicly lazy, what I've done is to copy
questions I've gotten and the answers I gave. This may work very well for you,
it may not. But, hey, life is cruel sometimes.
Most of these are lifted from the alt.surfing newsgroup, by the
way-
Doc's Most Excellent Ding Repair Lesson
Subject: Re: Glass as in "ding repair".
Yes, you are the man: Resin & Hardener, also tools, and pointers on how to repair a 8" long and 3" wide deck area right along that thin wood center line - what ever that is called. Is there a mail order place or are there local stores like boating etc. that carry stuff.
Doc, much thanks and hope to meet you sometimes.
H the H.
Okay, as I said in the email earlier this evening, I'm gonna give you some info on all this and also CC it to the mailing list to mebbe dispel a little of the misinformation that's been bouncing around on the subject. This is gonna get into some depth, so fasten your seat belts, it's gonna be a bumpy ride.First, materials with a few tools and then how to do your specific ding repair.
First off-Resin. Or, more accurately, resins. There are three kinds used in surfboard making and repair: laminating resin, sanding resin and glossing resin. They are a lot alike, but the biggest difference is that sanding and glossing resins contain a styrene wax.
What the hell is that for, you ask. Well, basic polystyrene (polyester) surfboard resin doesn't really harden if it's in contact with air. The wax, just a little bit dissolved in the resin itself, acts like an oil slick or a soap film and comes to the surface of the stuff and makes a very, very thin film between the resin and the air. That lets it harden enough to sand. Laminating resin doesn't have any wax, so later layers of resin-sanding and glossing, stick to it better.
Mostly, I use sanding resin for all my ding repairs. To get the wax off and let the next layer to stick to it, I use either a little acetone to wash the surface wax away or I just sand it. The surfboard factories buy 55 gallon drums of laminating resin and styrene wax by the 5 gallon bucket and make their own sanding resin. You add about as much wax as catalyst. (see below) Just a few drops in a ding-repair size batch
Now, you can't get surfboard resin at a hardware store or a marine store. What you do get is known (disparagingly) among us ding repair types as 'boat resin ". It is usually a waxed resin and it goes off reddish brown and brittle. Surfboard resin goes off water-clear and pretty tough. There are reasons for that, but I am gonna ignore them right now. I can do that.
I do boat repairs too, and get boat resin by the drum for that.
Epoxy boards and epoxy resin are a whole other thing that I'm gonna skip right now except for one thing- WEST resin sucks.
Okay, you went out and got some sanding resin. You also got Catalyst with it, or else you got ripped off- which is generally MEKP: Methyl Ethyl Ketone Peroxide, which has a material toxicity sheet about six pages long and stings like hell when I get it underneath a fingernail. Also comes in a couple of flavors, or more accurately, strengths. Generally, 'home use' catalyst is about 2% to 5% MEKP while the stuff for industrial use is a lot stronger concentration. It breaks down with age, heat and sunlight, so don't store it on the windowsill.If you try using tired catalyst....it gets ugly...and never hardens.
How much do you use? Well, that depends. I was a philosophy major, so I can say that about just about anything, but here it means something. You have to use more catalyst if it's cold or humid, less if it's hot or in the sunlight. The heat and the sun make the reaction go faster, cold and damp slower. Another thing to keep in mind is what is really going on: the catalyst is working to make longer molecules out of shorter ones. If you use more catalyst, the reaction goes faster and the molecules are not as long as they would be if you used less, which means they are kinda brittle. Use as little as you can get away with, in other words.
A bit more on catalyst: as the stuff goes off, it gives off heat. Exothermic reaction. So, if you are putting on a thick layer of glass or filler, use less catalyst because as it goes off, it heats up, which makes the resin go off faster, which gives off more heat, which....you get the picture. I once saw a board catch fire during a rushed repair-waaaay too much catalyst. Go easy, you have all winter, right?
Okay, all dings need some kind of filler. For that I use a powdery substance called Cabosil (or Aerosil) mixed with resin to the consistency of soft ice cream or vaseline. If you have to, use sugar. Wad it in, let it dry and either Surform before it gets completely hardened (that tool the Stanley company makes that looks like a cheese grater-get a small one) or sand it to shape when it has hardened completely. More on sanders and sanding in a bit. I usually use about an ounce (fluid ounce, that is) in the bottom of a paper cup and I wind up slowly stirring in about four times as much Cabosil powder, by volume. Use maybe 25% more catalyst with this stuff than you would with plain resin. Like coloring agent/pigment, Cabosil slows things down.
It sometimes helps to make a mold with masking tape for the filler. This will save you a lot of sanding later.
Glass Cloth is....pretty much glass cloth. There are surface treatments that are used on it, like the Volan process that makes nice old longboards that light green color, there are many, many different ways of weaving it, but what you need to be concerned with is the weight of it- how many ounces per yard. They range from 0.5 oz cloth (good for airplane models) to around 20 oz for really heavy stuff. Generally, though, 6 oz. or 8 oz. is the way to go. Cut with scissors, tape it down with masking tape taut across the ding, and when the resin is at a 'hard gel' stage, cut it along the tape with a razor blade or Stanley knife or my favorite, the #1 XACTO knife. Use a disposable 'chip brush' to brush in the resin so the cloth is completely saturated and just about transparent and brush out all the air bubbles, above and below the cloth. I use a natural rubber squeegee for big ding repairs, fixing busted boards and all that, but it took a good long time to learn that particular skill without major screwups that have to be ripped off and redone. You can do good work with a brush right away.
Use no more than 6 ounces of resin, maybe a dozen to fifteen drops of catalyst on a 65-70 degree (Fahrenheit) day.
Sand the edges down a little to feather in the cloth, make a smooth transition. Sand the whole area of the glass lightly. Hand sanding is fine, with maybe 120 grit paper- 3M is good, so is Norton Abrasives. If you are comfortable and experienced with power sanders, by all means use them except belt sanders. A good all-around ding repair sander is the random orbit type-I use a Porter Cable #7335 industrial type.
The nicest thing about power sanders is that nobody ever hand-sands a ding repair as much as they should. Believe me on this one.
Now, tape around the whole ding with masking tape, say an inch away from the glass edges. Brush on some resin that you have added just a few drops of acetone to-it makes it go on smoother. Take special care to get it on and into the edges of the cloth you sanded. When the resin is just past wet and getting tacky, remove the tape. The edge of your gloss will get real smooth-or it should, anyways. It doesn't take that much resin for this either-maybe a couple or three ounces. Use a lot of catalyst with this, say ten drops or even a little more. This is, after all, a very thin layer.
You may want to give the whole thing a little light sanding with wet and dry paper when it has really, really completely hardened. Start with 150 grit, sanding bigger and bigger areas (the ding itself, then an inch bigger, then a bit more ) as you go from 150 to 220 to 400 to 600. Again, the 3M or Norton wet&dry paper is very good. You can even polish it, if you have the right stuff-a disc polishing machine and the right polishing compound, but that's overkill.
Okay, if you must, you must...3M also makes the best polishing compounds for fiberglass use, available at a boat supply place or some auto supply places like NAPA. Make sure you get white compound...the red stuff stains resin permanently.
Okay, the materials list-
About a quart of sanding resin- you may need less, but more dings happen. Catalyst, a quart of acetone, wax paper cups (the 4 ounce or so size is good), popsicle sticks (for stirring and mixing), masking tape, Cabosil, glass cloth, razor blades, chip brushes and sandpaper. The red stuff is surf shop or mailorder, purple a hardware store item and the green stuff is boatyard/marine store OR hardware store (sometimes) OR surf shop or mailorder. You might also pick up some of the green painter's plastic gloves at the hardware store-makes life a whole lot easier.
Also, if possible, do this in a warm but very well ventilated place. No open flames and stuff like that, all these chemicals are REAL flammable, some fumes are explosive. If you have an Organic Vapor Mask, use it. I use one when I work indoors, both with resin and sanding.
For your particular deck ding along the stringer, I would
1) clean off any and all wax on it, in it or near it with a putty knife followed by a good scrubbing with acetone and a rag.
2) If the ding has torn the original cloth, pick up the edge with your clean putty knife and get out any crushed foam, etc.
3) Mix up a wet batch of cabosil and resin (thinner than usual, about as thick as yogurt)and, holding the ding open with your putty knife, slop it in, doing your best to get it into all the recesses and crevices of the ding. Let the old glass down gently, go have a beer and knock off for the night.
4) It's dry-sand it smooth and put the cloth to it, as I mentioned above. You will probably need a piece of cloth at least two inches longer and two wider than the whole ding. Cut to rough size with plain old scissors.
5) Sand and gloss, like above. Sand with wet and dry if you want to, it's gonna be under wax so it doesn't matter as much as it would on the bottom or on a rail.
Go surfing, or have another beer-you've earned it. Fact is, I might have one right now myself. I've earned it too. This writing is thirsty stuff.....
Okay, one last thing...mailorder sources for resin, Cabosil, cloth and such.
I use Destination Surf, but I am a wholesale account, buying gallons and gallons, and I don't think they sell retail. (note: as of 01/01/00 they do. See http://www.destinationproducts.com/ )For a better idea than I have of all the mailorder stuff and outlets,check out Pete Brown's enormous links page at . There is also Atlantic Surfing Materials (see Surfer Magazine ad) and some others. Also, most surf shops sell resin by the pint or quart. Just make sure you get sanding resin.
Good luck,
Doc, having a beer, thanks
So-the index- arranged by question with a few other topics tossed in.
Are you sick of this yet? Okay, wanna read some surf stories or go back
to the index
page.