Fitting New Valves in uPVC

Polymarine MarineTube Repair


Before you start any glueing please note: your workplace needs to be well ventilated, warm and dry. If the air is humid don't try to use the adhesive as it will bloom. Do not use a gas fire or naked flame heat source as the solvents are highly flammable. Do not use the adhesive if it has been mixed for more than 4 hours.

Keep Fire Extingusher Alongside
uPVC Material Construction

uPVC Material Construction

Materials needed:

Replacement Valve(s)
Valve spanner
2903 primer and cleaner
3026 two part adhesive
uPVC material
Paint brush (cut down to 20-25mm bristle)
Lint free cloth
Masking tape
Knife handle or rounded piece of hardwood

Valve Fitted to Tube

Cross section of valve tube when fitted.

1. Take out your old valve.
If the valve is glued on then heat the area with a hair drier or a hot air gun. This softens the adhesive and allows you to lift the edge and peel the valve back. The old adhesive will need to be sanded off. Check that the valve body will fit through the hole, if not make the hole bigger. If the valve is screwed together, unscrew and the back of the valve will be left inside the tube. To get this out make the hole bigger.

2. Prepare the outside of the tube.
Place the doubler in position and mark around it with a pencil. Using the masking tape, tape around the pencil mark leaving about a 3mm gap to allow for stretch in the material. Using your cloth wipe the surface of the doubler and the tube that is going to have the adhesive on with the 2903 solvent. Allow the solvent to flash off and wipe over again. The surface should become tacky. Allow to flash off. If you apply the adhesive too soon it will bloom (turn slightly white) the adhesive will need to be removed and new adhesive will have to be applied.

3. Apply Adhesive
Mix enough adhesive as directed on the tin. Brush onto the surface thinly, on both the tube and the doubler. The surface should look wet. Allow the adhesive to dry for at least 30 minutes.

4. Reapply Adhesive
Brush on a second coat on both surfaces. Lay a piece of polythene onto the tube adhesive. Put the cage of the valve into the tube and push to one side. Place the doubler into position making sure that the valve will sit squarely on the doubler, remove polythene. Work one side down with your knife handle, pressing hard. Then work the other side. Work from the middle to the outside of the patch. You must make sure that there is no air trapped between the surfaces. Take off tape and clean off any adhesive. The adhesive will turn brown if left on the surface.

tubevalveIf you are putting a valve into a RIB, assemble the valve with the doubler. Place into the hole and rub the fabric down. You will need to use your hand from the outside of the tube to support the fabric, so you can rub down hard enough.

5. Dry and Test
Leave to dry for at least six hours. When dry pump up the chamber. Tighten the valve, it should be tightened to a max of 10 lbs which is hand tight and just pinched up. Check for air leaks with soap solution and brush.

Information courtesy of Polymarine, inflatable boat repairer and supplier of inflatable boat spares and accessories, visit:

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