I am looking to see if any one has a source for alum/brass caps that are designed to fit inside iron pipes, that DO NOT USE PLASTIC TO JOIN THE CAP AND PIPE. Perhaps there is a homemade solution. Typically, I use 1/2" water pipe.
THANKS FOR YOUR HELP
Without an insulator between different metals, you will experience significant electrolytic corossion and your monuments will be short-lived. I have never heard of anyone making ceramic insulator washers or similar devices to prevent electrolysis.
Cliff's right...
A number of years ago we were working in an area in NW Oklahoma called the "Great Salt Plains". It's a natural saline seasonal lake (swamp?). The BLM had been in there in during WWII and set section corners that were aluminum (pot metal?) caps crimped onto 24"x3/4" steel pipe. I suppose this was due to the brass shortage for the War Effort.
The bi-metal corrosion was very efficient. We found almost every pipe severely rusted from the salts..with a wad of white 'ash' all globbed up on the top. When it dried it turned to powder.
You might try Surv-Kap in Tucson. They have a good selection and very good service.
They have a website.
DJJ
Cliff's right...
not planning on setting in points in the great salt plain or swampy seasonal lakes.
Yes, I am aware of the bi-metal problems
Berntsen or Surv-Kap.
www.berntsen.com
www.surv-kap.com
Call and TALK to soemone about your bi-metal concerns......they probably know better than anyone else.
> Berntsen or Surv-Kap.
>
> www.berntsen.com
>
> www.surv-kap.com
>
>
> Call and TALK to soemone about your bi-metal concerns......they probably know better than anyone else.
Any aluminum or brass cap with a stem will work inside a pipe. To avoid dissimilar metal corrosion you can use roof pitch or spray paint around the stem.
my last employer had boxes of aluminum rebar caps without the plastic insert but I don't know where they got them. I found some that had been in the ground for almost 20 years with no problem (rebar and cap still in love with each other ha ha).
Apparently they can be gotten though.
4 years ago or so a Surveyor I know got aluminum rebar caps from CSDS for pretty cheap without the plastic inserts.
I think a 3/4" rebar cap will go on a 1/2" g.i. pipe.
We generally used hydraulic cement to form the union between the aluminum cap and the iron pipe. You could set them in the swamp underwater if you had to. After a dozen or so, you got a good feel for how much cement dust and water you needed to make the perfect amount.
