View Single Post
  #3   Report Post  
Posted to rec.woodworking
Ian Malcolm[_2_] Ian Malcolm[_2_] is offline
external usenet poster
 
Posts: 77
Default Food safe sealer for raised beds

Leon lcb11211@swbelldotnet wrote in news:xumdnTZdQt-
:

On 4/1/2015 10:15 PM, MJ wrote:
Just got some cedar raised beds for vegetable garden. The cedar is
not finished. I want to preserve the cedar and not have it go
"silver", so looking around for a food safe UV sealer.

Several options showed up when I did a Google search: mineral
spirits, shellac, etc. (a number of products).


FWIW Mineral Spirits is simply a product thinner and absolutely does

not
provide protection.



I'm thinking of doing a shellac with a paraffin wax top on the inside
of the bed and then a UV stain on the the outside.

Anyone got some other options or thoughts on this?

MJ



Regardless of what you use short of an exterior paint the wood is going
to eventually fade in color unless you reapply often. Typically clear
finishes can last up to 2 years before needing to be reapplied.

Your local paint store is going to be able to give you the best advice
and what you can expect.



Bondaglass G4 clear pond sealer, (which is a moisture cured polyurethane)
overcoated while still ever so slightly tacky on the exterior and down to
the intended soil line with a UV resistant exterior polyurethane varnish
(NOT a low VOC one) to increase its UV resistance.

The G4 itself once fully cured doesn't outgass or leach anything
dangerous to delicate fish, so wont contaminate the soil if you wait a
week after its fully cured and wash it and the varnish down thouroughly
with soap and warm water to remove any surface film. Its not officially
food-safe but I'd be quite happy to regularly eat a dressed salad out of
a bowl finished with it then washed as described.

If you are in an urban area or within a few hundred yards of a moderately
busy through road, contamination from exhaust particulates will be a far
bigger concern than anything from a fully cured polyurethane finish.

N.B. G4 is a right b*****d to overcoat successfully if fully cured.
Either use a compatible paint/varnish while its still slightly tacky or
abrade thouroughly with a medium to coarse grit to mechanically key the
surface. *RTFM*

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL