1. Dipping in plywood
Dipping plywood is a term used to refer to the plywood which has been treated with chemicals by dipping the sheet into a chemical chamber. There are 2 types of dipping that are being used in the plywood industry –
- Sheet dipping
- Core veneer dipping
Both the dipping are used for different purposes and each has its own advantages and disadvantages. We will look deeply into each type of dipping and how they can be perceived.
2. Sheet Dipping
Sheet dipping is a term used to refer to the treatment of plywood with preservatives. This method is extensively used in the Indian plywood industry. The main purpose of this method is to treat the plywood so that it is resistant to borer/thermites.
2.1 METHOD
Once the plywood is pressed in the hot press, the sheet is then cut into the required shape and then allowed to cool. Once the plywood sheet is cooled, it is then passed through a chamber that contains the chemicals copper sulfate, sodium dichromate, chromic acid and boric acid. This chemical dipping is done to prevent the plywood to go bad early and to prevent thermite/borer infection.
2.2 ADVANTAGES
As mentioned earlier, chemical dipping is very much required to prevent the attack of thermite/borer to the plywood. Also, in many cases, this dipping method gives the plywood a distinct darker tinge because of the color of the chemicals used. This distinct darker color is appealing to many customers.
2.3 DISADVANTAGES
As such there are no disadvantages to the chemical dipping of the plywood if done properly. But, many manufacturers used the distinct dark color to their advantage. Most of the manufacturers actually dip the plywood sheets in a dark green-brownish color to give it a look of having been treated with preservatives. This will help then save cost on the chemicals, while at the same time, it goes at the similar cost of the actually dipped plywood.
2.4 CONCLUSION
Customers should be able to differentiate whether the plywood is proper chemical dipped or not. Customers can look for some indications to differentiate. When the plywood is proper chemical dipped, the color across the plywood is uniform and there are no visible marks/spots on the sheet. Whereas, if the plywood is just color water-dipped, it is difficult to maintain the uniformity of the color across the sheet.
3. CORE VENEER DIPPING
Core veneer dipping is a method used to dip the plywood veneer cores in the liquid so that it is visually appealing to the customer.
3.1 METHOD
Before the plywood is pressed, a core veneer is dipped in a hot chemical so that the core sheet will get a distinct red color. Then the veneer is dried and pressed. This method will give the plywood much darker red stripes.
3.2 ADVANTAGES
Although there are no distinct advantages to the core veneer dipping, this method will ensure that there is uniformity of the core veneer used in making the plywood.
3.3 DISADVANTAGES
In the plywood industry, the red core is extensively used because the red core is better than its counterparts. Red core implies that it has more strength and more quality. Because of this, there is a chance that manufacturers use this fact to their advantage and dip the core veneer which is of cheaper quality as well and press it. This will give an impression that actual red core is used in manufacturing, thus valuing the product at more cost.
3.4 CONCLUSION
One important fact to keep in mind is that there is no difference in quality if there is slightly less red core visible in the plywood. Uniform dark red cores in the plywood don’t signify more quality. One key thing to keep in mind is that, if the red core is used in the plywood and then it is perfectly calibrated, then 8*4 ft. plywood should weigh around 40-41 kgs. So when the customer is buying the plywood, if they have noticed the red cores/uniform red cores in the plywood sheet, it means that the plywood core veneer has undergone dipping. Customers should correlate those sheets with the approximate weight of the plywood as well, so they will not be duped into buying lower-grade plywood.