Best sealant for new DZR skin fittings

[stuartwineberg]

I am sure this has been done before on the forum but as always I struggle with the search function. So - DZR skin fittings, GRP yacht, likely to be going in with air temps just into double figures. If you quote me Sikaflex numbers it would be great if someone could also tell me if there are non marine non branded equivalents, like PU40

 

[VicS]

Sikaflex 291i is the "marine" polyurethane adhesive sealant

Sikaflex 221 is a similar adhesive sealant used in the construction industry

Puraflex 40 (PU40) is also a polyurethane adhesive sealant. Made by Everbuild which is a Sika company. Available from places like Toolstation

CT1 is a hybrid polymer adhesive sealant which has had good reports on the forums.

Stixall is a similar hybrid polymer. Like PU40 it is made by Everbuild and is also available from Toolstation.


When I built my boat, nearly 40 years ago, I used Seelastik on all the through hulls. It is (was) a linseed oil based sealant similar to putty in a tube. The joints are still sound.

 

[Tranona]

I always use a Polysulphide for skin fittings rather than a polyurethane as it does not fully set so can be removed relatively easily if need be.

 

[vyv_cox]

Nowadays I use Puraflex 40 for almost all above and below water fittings. It does set more strongly than polysulphide but I have yet to have any difficulty removing the fittings when needed.

I find Stixall is perticularly good for attaching wood to GRP as it is almost invisible. It does take a long time to cure though.

 

[ghostlymoron]

What it called and where from?

I always use a Polysulphide for skin fittings rather than a polyurethane as it does not fully set so can be removed relatively easily if need be.

 

[Minchsailor]

Be wary of using a polysulphide, as sulphuric acid is a by-product of the curing process and can cause corrosion. OK on inert material (fibreglass to plastic) but not so good when in contact with metals.

My preferred choice would be a mastic - Arbomast G is quite good. Non-setting, good adhesion, but can be taken apart.

 

[ghostlymoron]

Why would you want good adhesion in this situation? Ideally you don't want ANY adhesion, you are just compressing a sealant to form a seal, adhesion just makes it harder to dismantle.

 

[Alpha22]

Google for Geocel 201. From most builders merchants... (Not DIY warehouses). It's a popular choice for sealing double glazed units to brick.

Take care not to squeeze it all out of the joint. Wedge the flange up with the ends of 3 match sticks. Remove a day later.

 

[Tranona]

What it called and where from?

Either Boatlife Caulk or Arbomast Arbokol 1000. Latter probably more easily found.

 

[Kukri]

Be wary of using a polysulphide, as sulphuric acid is a by-product of the curing process and can cause corrosion. OK on inert material (fibreglass to plastic) but not so good when in contact with metals.

My preferred choice would be a mastic - Arbomast G is quite good. Non-setting, good adhesion, but can be taken apart.

Another vote for a simple mastic - Arbomast G is fine.

I once removed a mushroom vent from the after deck of a boat that was then forty eight years old and found the white lead paste that it had been bedded in was still liquid under it. But you can't get it now..

 

[adwuk]

I've use 3M 4200 with good results. Don't know how it compares with the others.