Glueing pump to hull

[fredct]

I have aluminum hull. Previous set up had the bilge pump screwed into a plexi sheet that was glued to hull. The net effect was to raise the min. water level which caused the glue to fail over time.


I want to glue the pump base directly to the hull (Sikka 295 seems like it would work for this) and then clip pump to base.



Is there a downside to this approach? Bracketing not really possible.

[Jammer]

It can work. It helps if you prepare (with sandpaper) the surface immediately (minutes) before applying adhesive. I have a small bilge pump mounted that way on my 12' aluminum boat, and it's stayed there for several years. I believe I used 5200 and let it sit for a week before I put the pump in.

[NorthCoastJoe]

I have an aluminum boat and recently added a bilge pump up forward in a tight space. I would not glue directly to the hull ever. I want to be able to see all areas of my hull.

I ended up getting creative, a few holes drilled in a stringer and zip ties solved the problem. You can glue some guides ( belt loops) onto the pump to hold your tie downs in place on the pump.

Not to mention in the future when you need to replace the pump the base will most likely not match what you have now. Then you have to bust off your old pump base.

[fredct]

Originally Posted by NorthCoastJoe

I have an aluminum boat and recently added a bilge pump up forward in a tight space. I would not glue directly to the hull ever. I want to be able to see all areas of my hull.

I ended up getting creative, a few holes drilled in a stringer and zip ties solved the problem. You can glue some guides ( belt loops) onto the pump to hold your tie downs in place on the pump.

Not to mention in the future when you need to replace the pump the base will most likely not match what you have now. Then you have to bust off your old pump base.

In my case, it is wide open. When dead, I would just multitool the entire thing off including the Sikkaflex and the base. Glueing also makes the dead space as small as possible. No final decision made.

[GordMay]

Fresh aluminum, with little oxidation, can often be bonded as is, or after a dry rag wipe. If heavy oxidation is present, then a light abrasion, followed by a solvent wipe is required.
I might be tempted to use an ITW “Plexus” adhesive product:
➥ https://itwperformancepolymers.com/r...terial-bonding
➥ https://itwperformancepolymers.com/r...exus-adhesives

[fredct]

I had to remove Sikkaflex 295 bonding a plexi lens to an Al frame. Took 10 hours which tells me that it will work for the pump, provided that the initial Al surface is perfectly dry, something not straightforward in a bilge!

[Jammer]

Originally Posted by GordMay

I might be tempted to use an ITW “Plexus” adhesive product

Also sold in smaller quantities as "devcon plastic welder." The stuff is great, faster cure than epoxy, inherently thicker, and less sensitive to surface preparation. I haven't tried it on aluminum but it works great on fiberglass and teak.

[GordMay]

Originally Posted by Jammer

Also sold in smaller quantities as "devcon plastic welder."...

Both are two-part methyl-methacrylate adhesives, carrying the 'Plexus' name,, available in 50ml twin cartridges:
Devcon 30500 50ml Plexus Plastic Welder ➥ https://sabreindustrial.com/dev30500/
Plexus IT410 50 ml ➥ https://www.rshughes.com/p/Plexus-MA.../plexus_it410/

[Matt Johnson]

Not answering your question, so sorry for the segue --- but we tried our best to keep DC current anyway from our aluminum boat's bilge. All it takes is some water, a little current leak in the pump or switch, and you'll shortly have all kinds of very expensive issues.

We installed a Whale gusher higher up and ran the pick-up hose down into the actual bilge. https://www.westmarine.com/rule-indu...kaAu3xEALw_wcB

The switch used air pressure and was mounted high and dry as well - https://www.westmarine.com/jabsco-sw...roducts__en_US

A lot of aluminum boat builders do as you're suggesting, but after welding in new hull plates for about 20% of my boat's bottom, I took every precaution I could after that.

[Russ]

I mounted my pump on a piece of thick aluminum with flathead recessed bolts
The heavy pieced AL keeps it upright and it barely moves in the bilge. I can take the whole thing out for repairs or cleaning.