Building a Sea Chest

[heynow2203]

Looks good

[mbmcdermott18]

Working on fairing the outside now. Knocked down the putty I spread over the outside and just went over it with some thickened resin.

Being able to make my own custom parts is going to be addictive. I already have a list of projects I want to do.

[mbmcdermott18]

I have been working on fairing the outside for the last two days.

I am about to start drilling and cutting on the box for the plumbing pumps etc.

Does anyone have any experience overdrilling holes then filling with epoxy and tapping them for machine screws?

I am thinking of mounting my pumps this way.

[Blue_Heron]

Originally Posted by mbmcdermott18

Being able to make my own custom parts is going to be addictive. I already have a list of projects I want to do.

I know exactly what you mean. It is very cool to be able to cut up a little cloth, mix up some goo to stick it all together and have a useful part you designed yourself.

Originally Posted by mbmcdermott18

Does anyone have any experience overdrilling holes then filling with epoxy and tapping them for machine screws?

I am thinking of mounting my pumps this way.

Over drilling and filling with epoxy is used for wood cored laminates to isolate the screw hole from the wood. You don't need to do it with a solid laminate.

Glass laminate isn't ideal for drill and tap for machine screw threads but it can be done. Just make sure you goop things up real well with 5200. And you might want to back it up with a nut on the outside.

Dave

[mbmcdermott18]

Got done trimming up the flange and put a radius on the corners. Also snapped a picture with the pumps just sitting in the box.

The wires will exit the rear and be sealed by blue sea cable grommets.

I am going to try the method Dave mentioned for fastening the pumps to the floor of the box.

After doing some reading on west system's website I was thinking of using thickened epoxy to seal everything up. Thought this might bond everything together well but would also be paintable so I could fillet the amount that squeezed out and make it look like there was no joint.

[SBD]

You might want to bed that in something more pliable and less permanent than cabosil thickened resin. Its going to be a prototype. You never know if you might need to make some changes, and thickened resin is brittle and will crack over time if there is any flexing.

Part looks good. Nothing more rewarding than an idea go from your mind to your hands.

[mbmcdermott18]

Well I had my first set back this afternoon. Tried to make the lid for the box myself out of some 1/2" acrylic that has been in the garage for a while. Couldn't get it right. The cuts and the radius were both jacked up. I am going to go by the glass shop tomorrow morning and get them to make one for me. Thinking I may get two just to carry one on the boat in the event the lid ever cracked it wouldn't cut a trip short.

Ordered some 316ss machine screws to hold the pumps and the lid down. I ended up tapping the floor of the box and will hold the pumps down in there with 316 8/32 screws.

For the lid I am going to tap the flange and run 1" 10/24 screws it. I am thinking I will use around 24 screws in the top. 8 on top and bottom and four on each side. I am going to draw it out in the morning.

I tapped a piece of the flange (the flange is solid laminate aprox 3/8") that I trimmed off and tapped it and ran a screw through it. then I put the piece on the floor and put a foot on either side of the screw and tried to pull it out with a pair of channel locks. I couldn't pull it out even after putting about a 1" bow in the 18" piece so I think it will be fine with that many screws in it. I am planning on putting some silicone or something to keep them from vibrating loose. Maybe loc tight? Any comments or suggestions?

I need to order some sheet gasket to cut my gasket. I was thinking of using 1/8 or 1/16 epdm rubber. There are several options and I don't know much about the different choices. The two that I recognized were silicone and epdm. Any suggestions on these types of materials?

[mbmcdermott18]

Nothing major going on in the last couple days just made a couple pieces to epoxy to the box that will screw to the hull to hold it in place. Also removed the rest of the pumps from the bilge and spent the day sanding the bilge yesterday. Got most of it knocked out.

Regrettably I will be out of town this weekend and unable to work on the boat. Will be back on Sunday and try to finish up the sanding and get a few holes filled with thickened epoxy. I am going to law down some awlgrip snow white in the bilge before I install the chest. I would like to get everything prepped so I can paint next weekend. We will see how it goes.

[mbmcdermott18]

The chest and bilge are painted and I have the chest partially assembled. I hope to put everything back in the bilge and install the sea chest this weekend.

I am wondering what to use for sealing the many threaded connections when plumbing the chest. In two areas I have to orient the fittings a certain way so they may not be dogged down as tight as possible. I am looking for a compound that will be strong enough to keep a tight seal.

I have asked a few folks and got different opinions from pipe dope teflon tape marine sealant etc. I was thinking of using 4200 so it would be strong enough to hold everything together but I would still have the ability to disassemble everything if need be.

Any ideas on what would be the best product for this application?

I will post a few pictures this weekend. I have been bad about remembering to take pictures as I go along.

[strick]

If it involves keeping your boat a float then I would use 4200 or 5200. Air mar recommends using 5200 to seal their threaded thru hull transducers.

strick