Will dovetail joints survive outside?
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- This topic has 20 replies, 10 voices, and was last updated 5 years, 11 months ago by Larry Geib.
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22 April 2018 at 6:36 am #531011
That fellow did a really nice job on the Dorade skylight, but that isn’t actually the best joint for that application, at least it wasn’t when I worked in a boatyard as a teenager.
The reason was that there are more linear inches of joint that can leak and start rot. A simple lap joint was considered more watertight over time and change of seasons and could be caulked more easily. Water tightness was considered more important than structural strength. Recaulking was easier. Sometimes the interior of the joint had a groove to pack with caulk before you screwed it all together.
With modern epoxies it probably makes no difference, but the old Dorade boxes and hatches were made like the attachment. One screw in each direction held it together. sometimes the screw and covering bung was installed vertically, depending on the height of the joint.
- This reply was modified 5 years, 12 months ago by Larry Geib.
- This reply was modified 5 years, 12 months ago by Larry Geib.
Attachments:
You must be logged in to view attached files.Also, if anyone’s interested, maybe for food-contact projects, of the 3 Titebond versions, both the original and III have clean Safety Data Sheets, II has 1 ingredient the others don’t have, and that seems to make it slightly more hazardous.
I’m not an expert on this, but I’m not so sure that the absence of hazards in the MSDS equates to food safe.
23 April 2018 at 1:23 am #531396I’m not an expert on this, but I’m not so sure that the absence of hazards in the MSDS equates to food safe.
The food industry uses MSDS sheets for that purpose.
http://www.foodsafetysite.com/educators/competencies/foodservice/chemicalsafety/chs1.html
If you do work for sale, you should have MSDS sheets available for all products used.
By law, you can demand a sheet for any product you purchase.
- This reply was modified 5 years, 12 months ago by Larry Geib.
The cited article describes a system for “chemical manufacturers and importers provide hazard information to users, such as foodservice workers.” Foodservice workers don’t just prepare food, they clean work areas and do other tasks that require chemicals like detergents, bleaches, and surfactants. I believe the page you are citing is explaining that any product on-site must have an associated MSDS, the MSDS must be in an effective filing system, and all workers must have free access. This is standard fare for industrial hygiene / safety. I do not think they are saying that this is how to establish that products can come in contact with food or be used to manufacture items that come in contact with food. That is just my belief and not a matter of knowledge or expertise.
I looked into this a little. It looks like the key idea is “food contact materials.” Different countries define and regulate them differently. In the US, the FDA is agency. They consider direct, secondary direct, and indirect food additives. Glues for cutting boards would be indirect food additives. The Code of Federal Regulations lists things that can be in adhesives that will have indirect food contact. See, https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=175.105 .
Again, I’m no expert, but it looks like the only way to know something can contact food is for the manufacturer to declare the product to be suitable for that purpose. It’s not done in the MSDS.
https://www.food-contact.com/news/2014/november/options-for-approving-new-food-contact-substances
2 May 2018 at 8:32 pm #538734If you are looking for what the manufacturer says, here is titebond’s
Are Titebond Glues safe to use?
All of our Titebond wood glues are safe to use and produce no harmful fumes. They meet the requirements of ASTM D4236 for safe use with arts and crafts. Titebond III Ultimate Wood Glue and Titebond II Premium Wood Glue have both been approved for indirect food contact. For this reason, it is the glue that we recommend for making cutting boards. We do recommend wearing gloves when working with the Titebond Polyurethane Glue because repeated use of the product with bare hands could lead to a sensitivity to those types of products.I wouldn’t ordinarily use that as the only guideline. Find out about the chemicals.
For half a century food tin manufacturers told us the plastic ( BPA) used with acid foods like tomato was safe. Turns out it’s an endocrine and estrogen disruptor and potential carcinogen.
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