Plastic Repair Products
I will break this into two sections.
Repair of the actual plastic, and refinishing the plastic.
Some of the products here, I will not be actively selling. I will endorse them as I have actually used them and for various reasons like them better than other products. If you cannot find them locally, I can get them for you but would need some lead time as I do not stock them for sale.
Identify the plastic
Yes easier said than done. But for you to make a good choice, this needs to be done.
Urethane Supply Company has a great chart for doing so.
Most plastic that is on vintage snowmobile's is either ABS/Polycarbonate or a blend of them, or Polyethylene. I will not recommend painting Polyethylene, but it can be welded.
Fiberglass is not plastic but some of the plastic cleaners can be used on it, but I don't find it necessary on vintage fiberglass.
Refinishing Plastic
Anytime that we paint plastic, we need to prep it. Prepping it really is more about cleaning than putting large scratches in it. We need to get any mold release agents off of the surface along with contaminants such as silicone from products like Armor All.
There are basically two processes for cleaning, one is with very harsh strong smelling solvents, wipe on, wipe off.
Example would be DuPont 2319S, 2322S or BASF 909 available from your local paint supplier.
Or this paste also from DuPont that I have made available in a 2 ounce bottle along with a gray scuff pad for lightly sanding and cleaning purposes. By repacking in a smaller quantity, it will save you having to purchase a large quantity that you will never use. You put a dab of the paste on the scuff pad which as been put in hot water, scuff until completely scuffed. Rinse one time, and then redo the entire process. When done and dried it should have a nice dull sheen to the plastic. The advantage of this system is that it doesn't smell nearly as bad as the harsh solvents, and you should be able to see when the item is dry if you have not cleaned thoroughly. This is good for most plastics used in snowmobiles with exception of Polyethylene (transparent and some black gas tanks) or ABS/Polycarbonate. For more information please check this out.
This also works great for Urethane and TPO (used on automobile bumpers)
New Item!
This paste can be used on ABS/Polycarbonate/Fiberglass Gel Coat and actually works well for cleaning off many contaminates prior to sanding but is not "required". Sanding before cleaning can "sand contaminates into the surface" hurting adhesion. This paste has chemicals that help to clean, chemically etch and sand the surface all at once.
The next step would be to use a adhesion promoter if required. You need to know your kind of plastic to verify this. Urethane and TPO do need adhesion promoter. By rights so does ABS/Polycarbonate if you go by the books. However, I have found that with Ski-Doo polycarbonate, it was not necessary. I will let you decide. Examples of this would be RM 868 AM865, Dupont 2330 or A-2330.
| New Item! To make purchasing adhesion promoter easer (cheaper) for the hobbiest, I have found a very good adhesion promoter that I am buying in bulk and repacking. This allows you to purchase in smaller quantities than a quart that most manufacturers require. This procuct is to be sprayed out of a gun after the plastic has been cleaned with the "Plastic Prep Package". |
Flex Additive: I have found this to be a contested subject. Some will say that the flex evaporates out when the paint dries so they say that you do not need it. This was true in Lacquer days, but we are not spraying lacquer today. Every paint chemist that I have dealt with say differently and I suspect they know more than most about the paint that they develop. I STRONGLY recommend using a flex agent on anything flexible at all. I even use it on Fiberglass and Polycarbonate/ABS. It also helps with rock chips and can be used in products applied to steel. I am offering Flex in 4 ounce bottles if you desire a smaller amount than a pint as normally found in Paint stores. Dupont 2350S and RM DF21/DF25 would be examples. Flex should be used in all undercoats, single stage topcoats, and clears. It should not be used in basecoat color.
NOTE Flex Add Cannot be used in 1K Products or epoxy primers!
| Flex Additive: Can be used in varying amounts from 4-8 ounces per quart |
| I can add Flex Additive directly into the mixed paint |
| I can add Flex Additive into the 2K aerosols for a $5.00 up charge per can |
Repair of physical issues with Plastic
There basically are two types of plastic repair. Structural which would be a break or crack in the actual plastic, and cosmetic such as a scratch.
Structural Repairs
I am a fan of welding if the plastic is broken or cracked when applicable. Fiberglass cannot be welded. I do like using the plastic welder as it heats up the plastic that you are welding and the rod at the same time. A good soldering iron can be used in place of a welder if you can control the heat properly and have a bit more patience. Note that the plastic welder has different heat settings.
I will be adding a page on the welding techniques of ABS and Polycarbonate.
You can sometimes take slivers of equivalent material and use for a welding rod. Great if you have good luck with that, I prefer using the proper rod. Old hoods or gas tanks can be of a different blend and/or have contaminants that may hinder your weld. This is especially true of a gas tank that has held oil for 2 strokes. Urethane Supply Company is probably the premier plastic repair company and has all of the rods available. If you desire to order them each, versus a package, I am making them available. You must choose which rod that you need in the drop down box.
| Urethane Supply Co. Plastic 1/8 inch Welding Rod Each or approximately 1 foot. |
Since I am doing some custom welding with airless/nitrogen welder. I have sourced some more "commercial" type plastic Welding Rod. By purchasing in bulk, the price is considerably cheaper. BUT, most of this will not go through the pre heat tube of a airless welder that was designed for 1/8 rod.
| Red 1/4 Polycarbonate/Lexan Welding Rod.
Good for Rupps.and other sleds with red polycarbonate hoods. This
can be used to weld up cracks, insert patches etc. It is not an
exact match, but a good camouflage. Very nice rod to work with.
Note this is 4 times the rod per foot as 1/8 inch at the same price!!! Note, for "each" unit that you purchase, you will receive one foot. |
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| Yellow 1/4 Polycarbonate/Lexan Welding Rod.
Good for Ski-Doo.and other sleds with Yellow polycarbonate hoods.
This can be used to weld up cracks, insert patches etc. It is not
an exact match as it is a bit brighter, but a good camouflage.
Very nice rod to work with. Note this is 4 times the rod per foot
as 1/8 inch at the same price!!! Note, for "each" unit that you purchase, you will receive one foot. |
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Bonding of These products can also be done. I recommend using a mesh on the back side with the bonding material if structural at all. My favorite product for this is Dominion Sure Seal Plastic Surgery. as a all purpose product. For just finish work, I prefer the Pliogrip Finishing Cream, but this requires a gun to dispense it with also. Here I am using Plastic Surgery on a Urethane hood, but this would apply to many different products. Please note, adhesion promotion and cleaning before applying these types of plastics is essential for proper results.
Tips for Success
When welding, allow to cool thoroughly before stressing the repair.
When Bonding, let the bonding material dry adequately. Adhesion is gained as the product cures. If sanding too soon, the product will roll up on the edge.
Do not attempt to paint Polyethylene
When sanding plastic, use fine grit sand paper when feathering old paint off.
When sanding repair material such as plastic surgery, I like to start with 180 or 240 grit. Going to course can leave deep scratches and fuzzy strands. Sanding too fine can create unwanted heat.
Clean, Clean, Clean