System 6 Urethane Coating Application - Raft Repair Solutions

Safety

Always work in a well ventilated area out of the sun, wear protective gloves (nitrile is best), clothing, eye protection and a fresh air respirator if possible. Do not breath the dust created from abrading the area, the fumes from the primer, coating, etc. or have the product contact your skin. Don’t mix the urethane with electric mixing tools. This product is highly flammable so do not use around any ignition source. See MSDS for further info.

Learn More

Preparation

Cut away or re-glue all loose pieces of material. If you are trying to seal pin hole leaks you must apply this urethane coating to the boat un-inflated. Otherwise inflate the boat so it is firm, but not all the way up to full operating pressure (about 1.5 psi). If possible, scrub the area with an abrasive pad like Scotch-Brite with soapy water and rinse completely. Then wipe the area with solvent (Isopropyl Alcohol or MEK) and allow to dry (MEK will stain PVC and similar fabric so it must be used sparingly. Try to not touch the cleaned area.
For Hypalon and Urethane fabrics, lightly buff or abrade the area that you plan to cover with one of the abrasive wheels that we sell in a variable speed drill. If you use the power tool approach be very careful to not grind through the coating and expose the cloth underneath if possible. Be sure to remove all the fabric’s gloss so it has a dull, almost suede like appearance. Abrading the surface is the single most important step in preparing your boat because urethane coatings will not stick to a surface that has not been properly cleaned and abraded. Blow the dust away. Mask the area using a good quality 2” masking tape.

Primer Application

Use System 6 U Primer (1-part) for Urethane Coated Fabrics or System 6 HP Primer (1-part) for Hypalon. Most PVC materials do not require a primer. Use a new brush with natural bristles (synthetic bristles may melt and contaminate your work). You can also apply the primer with paper towels. Apply the primer as thinly as possible while ensuring that you are getting complete coverage, do not allow the primer to “pool”. Do not work in direct sunlight. The primer is very thin and will run so make sure the area has been properly masked.
Let the primer dry to a tacky state, usually about 10 minutes on a warm day. Apply the urethane within 2 hours of primer application.
It is important to understand that our kits are unique to one another only because of the primer – a PVC kit will not have primer … a hypalon kit will have a 1 part primer & the urethane kit will also have a 1 part primer.
If you are applying System 6 to a hypalon boat today but six months down the road, you decide to add another layer for further protection, now you would need the 1 part urethane primer because you would be covering urethane and not hypalon. Make sense?

Urethane Application

You may apply the urethane with a brush or roller. Rolling is easiest, so here is the directions for applying it with a 4” short nap roller. Rolling the urethane leaves a semi-textured finish.
It is important that parts A & B be measured equally prior to pigment being added. If you are using pigment, add it to Part A BEFORE mixing parts A & B together mixing thoroughly. It is very important that the pigment is stirred and mixed well into Part A because it will not disperse properly when Part B is added due to reduced frictional density.
To mix the urethane, pour equal amounts of Parts A & B into a clean container being sure to measure accurately. You can get a disposable paint bucket from Lowe’s or Home Depot or you local hardware to mix in. Add the Accelerator THAT IS INCLUDED IN THE KIT and mix vigorously for at least 5 minutes (this is very important). Be sure to scrape the sides and bottom of the container while stirring. Do not mix more than can be applied in 45 minutes. Begin applying the urethane immediately after you finish mixing unless you think it is too thin, in which case you can let it stand for 10–15 minutes and it will thicken. You cannot over mix but you can certainly under mix.
Do not work in direct sunlight. Do not breathe the fumes or get the urethane on your skin.
Begin coating the area where you want the thickest layer first. You can build thicker applications by applying multiple coats. Wait 15-20 minutes between coats. If sagging or running occurs, allow more time between coats. Try not to let the urethane come all the way up to your masking until the last coat. Working from the center outward to the masking will allow for optimal build and symmetry. Remove the masking after the final has started to cure (about 30 minutes from when you finish rolling). *** If you wait more than two hours to add another coat, the urethane primer will be needed to go atop the surface that you want to re-coat.

Recommended thickness: Bottom Chafer – 30 to 40 mils (1/32”= 31 mils). Other areas – 10 to 20 mils. Each rolled coat should add about 4 to 6 mils. So bottom chafers should be 7 coats at the thickest point.

The Cure

Urethane cures very slowly in ideal weather conditions (constant 75° F & low humidity). It cures slower in cooler temps and faster in warmer temps. Without the System 6 Accelerator it will reach final cure in 10 days. Using the Accelerator it will fully cure in 4 days. During the cure period do not allow the urethane to touch itself. If possible leave your inflatable boat inflated and unmoved until the urethane has fully cured. The urethane will be dry to the touch in one day but final cure takes 4 days using the Accelerator. Do not cure in direct sunlight.

Tips

Have a few spare rollers and roller covers.
Have at least one spare mixing bucket.
Have plenty of rags and toluene to spot clean primer and urethane drips.
Prep and application take time, do it right and don’t rush it and you will get predictable results.
You will have a 3 hour re-coat window at 75° F, longer at cool temps and shorter at warmer.
A 2 Quart Kit (1 qt. of Part A & 1 qt. of Part B) covers approximately 12 sq. ft at 30-40 mils.
Primer ratio to urethane is theoretically 1:8