Last week’s post on replacement blades for silver knives focused on the actual knife blade. That is to say the portion of the bade that is exposed after it has been secured into the knife handle. Today, with many thanks to Joseph Grenon, owner and operator of Awesome Metals, an antique metal repair and refurbishing business near me in the DC area, our discussion will continue by taking a look at what goes on inside the handle.
Adhesives for Replacement Blades
Joseph wrote me a note explaining a few technical issues about the adhesives used when fitting replacement blades. He has kindly given permission for me to share it with you.
“I thought I would mention a couple of things.
- The glue that holds the blade in the handle is usually rosin. This is pretty much the same stuff fiddler’s use on their bows and rodeo riders use on their ropes to get a better grip. At room temperature, it set to a hard glossy appearance.
- When heated, it melts and as it gets hotter it liquifies to the consistency of molasses or honey. It can become quite flammable at high temps.
- It is very reversible. It is sometimes mixed with whiting or some other inert powder to stretch the rosin.
- When put in the dishwasher, the rosin will expand, usually forcing the blade out of the handle. Over heating or heating too quickly can cause the rosin to expand quickly and forcefully and can result in a burst handle.
- Blades are frequently soldered to the handle after being set with rosin, this helps keep them in place if they are exposed to heat.
- The solder used may be a 50/50 tin lead mixture, but it is hard to predict. If I do this, I use a pure tin solder to preclude the lead issues.
- The plated blades I have seen are usually steel. The plating is quite thin as you note, and it is prone to wear off the edges quickly with use, and immediately if sharpened. The exposed steel is vulnerable to oxidation, rust. I doubt there is any lead in those blades, but I would not risk guaranteeing it.
- Are typically set with a hard cement that is temperature and dishwasher safe.
- Newer flatware is set this way at the factory, and I will occasionally set stainless blades this way for people who wish to be able to use them in the dishwasher.
- The down side of the cement is that it is not reversible. To remove a blade set in this way I have to cut it off at the handle, then drill into the hollow of the handle and excavate the tyne and the cement. There is risk of damage to the handle when doing this.
- The same rosin is used as weight, in weighted or cement filled sterling silver. I have come across filings of tar, plaster and other mixtures that can be annoying.”
Thank you Joseph – there is an awful lot of food for thought in the paragraphs above.
I’d like to reiterate that Joseph and I have no financial relationship. He is receiving this shout-out on Silver Magpies because he was nice enough to write to me with this expertise. I asked him if I could share it with you.
When I finally get around to sending him the broken spoon sitting on my desk, I’ll pay full retail price for the repair, the same as any other customer.
I’ve said it before, but freedom of opinion on Silver Magpies is too important to me to risk tainting through marketing relationships, gifts or advertisements.