Radar Arch Filler 89 340 EC

wileecoyote

wileecoyote

Member
TECHNICAL Contributor
Oct 18, 2008
949
Southern MD/ Potomac river
Boat Info
1989 340 EC
Engines
7.4LX2 Hurth 630A Drives
6.5Kw QS Genny
Removed the radar arch to pull the motors and was puzzled by something with the area where it bolts to the hull. This is a photo of the mounting.

Once I removed it there is a piece of plywood that is against the fiberglass hull surface, but to fill the angled area it was filled with some type of filler? It looks like a lighter version of body filler maybe? Looks airy, but feels chaulky like body filler. This is the full sized image link . Does anyone know what this is, or what I can use to replace it? I was just planning on trying body filler, but the auto body filler I know of is much heavier than this stuff. Again this fills the uneven area between the outer edge of the arch and the plywood that contacts the hull area.
100_2358.JPG
 
Looks like foam... just like it is so old it has turned chalky...

Wanted to take a second to say thank you for all of the great info you have contributed to this site I have had more then one question answered by your great posts...:thumbsup:
 
No problems, Haven't had much to post lately, as I have been working on engine replacement and some other bilge items.
I agree it looks foamy, but it has to get hard in order to support the compression from the bolts holding the arch to the side of the hull. It almost appears to be a foamy type of filler material, but gets hard with cure.
The stuff is hard, but if you hit it against something it will crack open. I swear it has to be some type of lightweight filler material, just hoping someone with more know how can point me to the correct product.
 
Have you tried to Pm Frank Webster? He restored a 340ec and you know as the rest of us, the man knows his stuff!
What happened to your engines? Just hours or a failure?

Take care,
 
Never had Fresh water cooling as the boat was originally in the Great lakes. When I got it the internal rot from Raw Water cooling in the Chesapeake had taken its toll. Last year I was getting water in the cylinders, replaced manifolds and risers to no avail. The head bolts were rusted off outside the valve covers, so I decided it was time for both the be replaced. Trouble now, is getting someone at the marina to operate the boom lift to set them in. Winter hours, no ones around!
 
Did you rebuild the originals? Or go back to 7.4 or upgrade to the 8.1's? Atleast we only have a few more months and spring will be upon us..
 
I bought reman'd long blocks, because I was afraid the block was too rotted away on the inside. I stayed with the original 7.4 due to cost. After speaking to someone at PPT he explained the issues with an 8.1 conversion. The cost in trans and prop changes ( if the right props would even fit in the pockets) was more than I wanted to absorb. He suggested a 6.2L would be a more suitable, but again it was more cost effective to stay with the original designed powertrain. I believe they have a write up on the webpage, which led me to contact them.
 
I see good luck with the repower... good info to know. Keep us posted and glad to see you posting on CSR again.
 
I have been trying to research something I could use here. Has anyone had any experience with pourable urethane foam? The material that was in here was just a filler between the bolt head on the outer section of the arch and a piece of plywood that butted up against the hull. The material that came out is very rigid, but super light weight. Its somewhat chalky and can be broken apart by hand.
If anyone has worked with urethane foam I am interested in its properties and where I can get some to test it.
 
I have used the urethane expanding closed cell foam. You can order it from US Composites in Florida. I think I used the 4# kit for filling in the new supports on my boat where the gas tank is mounted. I did not use it in my new stringers, but that is the general usage.

http://www.uscomposites.com/foam.html
 
Did it get hard, or was it spongy like the expanding foam I'm thinking of? The stuff I have reminds me of a more cellulose gypsum board.
 
It gets very hard when cured, almost rock hard. Not spongy at all.
 
Thats probably what I'm looking for. I will have to order some and do some testing with it to judge the expansion. I'm almost thinking they may have loosely mounted the arch and then poured it in the holes afterward to take up the gap and make it fit nice and tight. I just need to be sure no to overdo it. Maybe I can take water and measure the area to be filled and experiment with the proper mixture so I dont end up with it bulging out.
Thanks for the info!
 
They have formulas or charts for how much product is needed to fill a certain cubic area.

You may have to ask them when you call to order. They are very good to deal with.
 
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